diff --git a/Source/Core/Core/Analytics.cpp b/Source/Core/Core/Analytics.cpp
index 436a117029..c5349fe28e 100644
--- a/Source/Core/Core/Analytics.cpp
+++ b/Source/Core/Core/Analytics.cpp
@@ -1,13 +1,14 @@
 #include "Core/Analytics.h"
 
 #include <array>
-#include <cinttypes>
-#include <mbedtls/sha1.h>
 #include <memory>
 #include <mutex>
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+#include <mbedtls/sha1.h>
+
 #if defined(_WIN32)
 #include <windows.h>
 #elif defined(__APPLE__)
@@ -21,7 +22,6 @@
 #include "Common/CPUDetect.h"
 #include "Common/CommonTypes.h"
 #include "Common/Random.h"
-#include "Common/StringUtil.h"
 #include "Common/Timer.h"
 #include "Common/Version.h"
 #include "Core/Config/MainSettings.h"
@@ -87,7 +87,7 @@ void DolphinAnalytics::GenerateNewIdentity()
 {
   const u64 id_high = Common::Random::GenerateValue<u64>();
   const u64 id_low = Common::Random::GenerateValue<u64>();
-  m_unique_id = StringFromFormat("%016" PRIx64 "%016" PRIx64, id_high, id_low);
+  m_unique_id = fmt::format("{:016x}{:016x}", id_high, id_low);
 
   // Save the new id in the configuration.
   SConfig::GetInstance().m_analytics_id = m_unique_id;
@@ -104,7 +104,7 @@ std::string DolphinAnalytics::MakeUniqueId(std::string_view data) const
   std::string out;
   for (int i = 0; i < 8; ++i)
   {
-    out += StringFromFormat("%02hhx", digest[i]);
+    out += fmt::format("{:02x}", digest[i]);
   }
   return out;
 }
diff --git a/Source/Core/Core/BootManager.cpp b/Source/Core/Core/BootManager.cpp
index 92fec9575b..755698b1a9 100644
--- a/Source/Core/Core/BootManager.cpp
+++ b/Source/Core/Core/BootManager.cpp
@@ -22,12 +22,13 @@
 #include <array>
 #include <string>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/Config/Config.h"
 #include "Common/FileUtil.h"
 #include "Common/IniFile.h"
 #include "Common/Logging/Log.h"
-#include "Common/StringUtil.h"
 
 #include "Core/Boot/Boot.h"
 #include "Core/Config/MainSettings.h"
@@ -283,7 +284,7 @@ bool BootCore(std::unique_ptr<BootParameters> boot, const WindowSystemInfo& wsi)
     for (unsigned int i = 0; i < SerialInterface::MAX_SI_CHANNELS; ++i)
     {
       int source;
-      controls_section->Get(StringFromFormat("PadType%u", i), &source, -1);
+      controls_section->Get(fmt::format("PadType{}", i), &source, -1);
       if (source >= SerialInterface::SIDEVICE_NONE && source < SerialInterface::SIDEVICE_COUNT)
       {
         StartUp.m_SIDevice[i] = static_cast<SerialInterface::SIDevices>(source);
@@ -297,7 +298,7 @@ bool BootCore(std::unique_ptr<BootParameters> boot, const WindowSystemInfo& wsi)
       int source;
       for (unsigned int i = 0; i < MAX_WIIMOTES; ++i)
       {
-        controls_section->Get(StringFromFormat("WiimoteSource%u", i), &source, -1);
+        controls_section->Get(fmt::format("WiimoteSource{}", i), &source, -1);
         if (source != -1 && g_wiimote_sources[i] != (unsigned)source &&
             source >= WIIMOTE_SRC_NONE && source <= WIIMOTE_SRC_REAL)
         {
@@ -335,12 +336,14 @@ bool BootCore(std::unique_ptr<BootParameters> boot, const WindowSystemInfo& wsi)
     {
       if (Movie::IsUsingMemcard(i) && Movie::IsStartingFromClearSave() && !StartUp.bWii)
       {
-        if (File::Exists(File::GetUserPath(D_GCUSER_IDX) +
-                         StringFromFormat("Movie%s.raw", (i == 0) ? "A" : "B")))
-          File::Delete(File::GetUserPath(D_GCUSER_IDX) +
-                       StringFromFormat("Movie%s.raw", (i == 0) ? "A" : "B"));
-        if (File::Exists(File::GetUserPath(D_GCUSER_IDX) + "Movie"))
-          File::DeleteDirRecursively(File::GetUserPath(D_GCUSER_IDX) + "Movie");
+        const auto raw_path =
+            File::GetUserPath(D_GCUSER_IDX) + fmt::format("Movie{}.raw", (i == 0) ? 'A' : 'B');
+        if (File::Exists(raw_path))
+          File::Delete(raw_path);
+
+        const auto movie_path = File::GetUserPath(D_GCUSER_IDX) + "Movie";
+        if (File::Exists(movie_path))
+          File::DeleteDirRecursively(movie_path);
       }
     }
   }
diff --git a/Source/Core/Core/Config/MainSettings.cpp b/Source/Core/Core/Config/MainSettings.cpp
index 9497bba6d2..9979017cdc 100644
--- a/Source/Core/Core/Config/MainSettings.cpp
+++ b/Source/Core/Core/Config/MainSettings.cpp
@@ -4,9 +4,10 @@
 
 #include "Core/Config/MainSettings.h"
 
+#include <fmt/format.h>
+
 #include "AudioCommon/AudioCommon.h"
 #include "Common/Config/Config.h"
-#include "Common/StringUtil.h"
 #include "Core/HW/EXI/EXI_Device.h"
 #include "Core/HW/SI/SI_Device.h"
 #include "Core/PowerPC/PowerPC.h"
@@ -56,19 +57,19 @@ const ConfigInfo<std::string> MAIN_BBA_MAC{{System::Main, "Core", "BBA_MAC"}, ""
 
 ConfigInfo<u32> GetInfoForSIDevice(u32 channel)
 {
-  return {{System::Main, "Core", StringFromFormat("SIDevice%u", channel)},
+  return {{System::Main, "Core", fmt::format("SIDevice{}", channel)},
           static_cast<u32>(channel == 0 ? SerialInterface::SIDEVICE_GC_CONTROLLER :
                                           SerialInterface::SIDEVICE_NONE)};
 }
 
 ConfigInfo<bool> GetInfoForAdapterRumble(u32 channel)
 {
-  return {{System::Main, "Core", StringFromFormat("AdapterRumble%u", channel)}, true};
+  return {{System::Main, "Core", fmt::format("AdapterRumble{}", channel)}, true};
 }
 
 ConfigInfo<bool> GetInfoForSimulateKonga(u32 channel)
 {
-  return {{System::Main, "Core", StringFromFormat("SimulateKonga%u", channel)}, false};
+  return {{System::Main, "Core", fmt::format("SimulateKonga{}", channel)}, false};
 }
 
 const ConfigInfo<bool> MAIN_WII_SD_CARD{{System::Main, "Core", "WiiSDCard"}, false};
diff --git a/Source/Core/Core/ConfigLoaders/GameConfigLoader.cpp b/Source/Core/Core/ConfigLoaders/GameConfigLoader.cpp
index 98bc1a5dfd..418a2c83d2 100644
--- a/Source/Core/Core/ConfigLoaders/GameConfigLoader.cpp
+++ b/Source/Core/Core/ConfigLoaders/GameConfigLoader.cpp
@@ -15,6 +15,8 @@
 #include <utility>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/CommonPaths.h"
 #include "Common/Config/Config.h"
 #include "Common/FileUtil.h"
@@ -23,8 +25,6 @@
 #include "Common/MsgHandler.h"
 #include "Common/StringUtil.h"
 
-#include "Common/Config/Config.h"
-#include "Core/Config/GraphicsSettings.h"
 #include "Core/Config/SYSCONFSettings.h"
 #include "Core/ConfigLoaders/IsSettingSaveable.h"
 
@@ -54,7 +54,7 @@ std::vector<std::string> GetGameIniFilenames(const std::string& id, std::optiona
 
   // INIs with specific revisions
   if (revision)
-    filenames.push_back(id + StringFromFormat("r%d", *revision) + ".ini");
+    filenames.push_back(id + fmt::format("r{}", *revision) + ".ini");
 
   return filenames;
 }
@@ -292,7 +292,7 @@ void INIGameConfigLayerLoader::Save(Config::Layer* layer)
 
   // Try to save to the revision specific INI first, if it exists.
   const std::string gameini_with_rev =
-      File::GetUserPath(D_GAMESETTINGS_IDX) + m_id + StringFromFormat("r%d", m_revision) + ".ini";
+      File::GetUserPath(D_GAMESETTINGS_IDX) + m_id + fmt::format("r{}", m_revision) + ".ini";
   if (File::Exists(gameini_with_rev))
   {
     ini.Save(gameini_with_rev);
diff --git a/Source/Core/Core/ConfigLoaders/NetPlayConfigLoader.cpp b/Source/Core/Core/ConfigLoaders/NetPlayConfigLoader.cpp
index 5e3aa22b59..2cc63eb146 100644
--- a/Source/Core/Core/ConfigLoaders/NetPlayConfigLoader.cpp
+++ b/Source/Core/Core/ConfigLoaders/NetPlayConfigLoader.cpp
@@ -6,6 +6,8 @@
 
 #include <memory>
 
+#include <fmt/format.h>
+
 #include "Common/CommonPaths.h"
 #include "Common/Config/Config.h"
 #include "Common/FileUtil.h"
@@ -100,10 +102,12 @@ public:
         layer->Set(Config::MAIN_GCI_FOLDER_A_PATH_OVERRIDE, path + "Card A");
         layer->Set(Config::MAIN_GCI_FOLDER_B_PATH_OVERRIDE, path + "Card B");
 
-        const std::string file = File::GetUserPath(D_GCUSER_IDX) + GC_MEMCARD_NETPLAY + "%c." +
-                                 m_settings.m_SaveDataRegion + ".raw";
-        layer->Set(Config::MAIN_MEMCARD_A_PATH, StringFromFormat(file.c_str(), 'A'));
-        layer->Set(Config::MAIN_MEMCARD_B_PATH, StringFromFormat(file.c_str(), 'B'));
+        const auto make_memcard_path = [this](char letter) {
+          return fmt::format("{}{}{}.{}.raw", File::GetUserPath(D_GCUSER_IDX), GC_MEMCARD_NETPLAY,
+                             letter, m_settings.m_SaveDataRegion);
+        };
+        layer->Set(Config::MAIN_MEMCARD_A_PATH, make_memcard_path('A'));
+        layer->Set(Config::MAIN_MEMCARD_B_PATH, make_memcard_path('B'));
       }
 
       layer->Set(Config::MAIN_GCI_FOLDER_CURRENT_GAME_ONLY, true);
diff --git a/Source/Core/Core/ConfigManager.cpp b/Source/Core/Core/ConfigManager.cpp
index 1aa1b3f0a6..56a3003d0f 100644
--- a/Source/Core/Core/ConfigManager.cpp
+++ b/Source/Core/Core/ConfigManager.cpp
@@ -11,6 +11,8 @@
 #include <sstream>
 #include <variant>
 
+#include <fmt/format.h>
+
 #include "AudioCommon/AudioCommon.h"
 
 #include "Common/Assert.h"
@@ -117,13 +119,13 @@ void SConfig::SaveGeneralSettings(IniFile& ini)
   general->Get("ISOPaths", &oldPaths, 0);
   for (int i = numPaths; i < oldPaths; i++)
   {
-    ini.DeleteKey("General", StringFromFormat("ISOPath%i", i));
+    ini.DeleteKey("General", fmt::format("ISOPath{}", i));
   }
 
   general->Set("ISOPaths", numPaths);
   for (int i = 0; i < numPaths; i++)
   {
-    general->Set(StringFromFormat("ISOPath%i", i), m_ISOFolder[i]);
+    general->Set(fmt::format("ISOPath{}", i), m_ISOFolder[i]);
   }
 
   general->Set("RecursiveISOPaths", m_RecursiveISOFolder);
@@ -224,9 +226,9 @@ void SConfig::SaveCoreSettings(IniFile& ini)
   core->Set("BBA_MAC", m_bba_mac);
   for (int i = 0; i < SerialInterface::MAX_SI_CHANNELS; ++i)
   {
-    core->Set(StringFromFormat("SIDevice%i", i), m_SIDevice[i]);
-    core->Set(StringFromFormat("AdapterRumble%i", i), m_AdapterRumble[i]);
-    core->Set(StringFromFormat("SimulateKonga%i", i), m_AdapterKonga[i]);
+    core->Set(fmt::format("SIDevice{}", i), m_SIDevice[i]);
+    core->Set(fmt::format("AdapterRumble{}", i), m_AdapterRumble[i]);
+    core->Set(fmt::format("SimulateKonga{}", i), m_AdapterKonga[i]);
   }
   core->Set("WiiSDCard", m_WiiSDCard);
   core->Set("WiiKeyboard", m_WiiKeyboard);
@@ -323,7 +325,7 @@ void SConfig::SaveUSBPassthroughSettings(IniFile& ini)
 
   std::ostringstream oss;
   for (const auto& device : m_usb_passthrough_devices)
-    oss << StringFromFormat("%04x:%04x", device.first, device.second) << ',';
+    oss << fmt::format("{:04x}:{:04x}", device.first, device.second) << ',';
   std::string devices_string = oss.str();
   if (!devices_string.empty())
     devices_string.pop_back();
@@ -399,7 +401,7 @@ void SConfig::LoadGeneralSettings(IniFile& ini)
     for (int i = 0; i < numISOPaths; i++)
     {
       std::string tmpPath;
-      general->Get(StringFromFormat("ISOPath%i", i), &tmpPath, "");
+      general->Get(fmt::format("ISOPath{}", i), &tmpPath, "");
       m_ISOFolder.push_back(std::move(tmpPath));
     }
   }
@@ -496,12 +498,12 @@ void SConfig::LoadCoreSettings(IniFile& ini)
   core->Get("SlotB", (int*)&m_EXIDevice[1], ExpansionInterface::EXIDEVICE_NONE);
   core->Get("SerialPort1", (int*)&m_EXIDevice[2], ExpansionInterface::EXIDEVICE_NONE);
   core->Get("BBA_MAC", &m_bba_mac);
-  for (int i = 0; i < SerialInterface::MAX_SI_CHANNELS; ++i)
+  for (size_t i = 0; i < std::size(m_SIDevice); ++i)
   {
-    core->Get(StringFromFormat("SIDevice%i", i), (u32*)&m_SIDevice[i],
+    core->Get(fmt::format("SIDevice{}", i), (u32*)&m_SIDevice[i],
               (i == 0) ? SerialInterface::SIDEVICE_GC_CONTROLLER : SerialInterface::SIDEVICE_NONE);
-    core->Get(StringFromFormat("AdapterRumble%i", i), &m_AdapterRumble[i], true);
-    core->Get(StringFromFormat("SimulateKonga%i", i), &m_AdapterKonga[i], false);
+    core->Get(fmt::format("AdapterRumble{}", i), &m_AdapterRumble[i], true);
+    core->Get(fmt::format("SimulateKonga{}", i), &m_AdapterKonga[i], false);
   }
   core->Get("WiiSDCard", &m_WiiSDCard, false);
   core->Get("WiiKeyboard", &m_WiiKeyboard, false);
@@ -702,7 +704,7 @@ void SConfig::SetRunningGameMetadata(const std::string& game_id, const std::stri
   else if (title_id != 0)
   {
     m_debugger_game_id =
-        StringFromFormat("%08X_%08X", static_cast<u32>(title_id >> 32), static_cast<u32>(title_id));
+        fmt::format("{:08X}_{:08X}", static_cast<u32>(title_id >> 32), static_cast<u32>(title_id));
   }
   else
   {
diff --git a/Source/Core/Core/CoreTiming.cpp b/Source/Core/Core/CoreTiming.cpp
index d1c2d463ff..4249c3a88d 100644
--- a/Source/Core/Core/CoreTiming.cpp
+++ b/Source/Core/Core/CoreTiming.cpp
@@ -11,12 +11,12 @@
 #include <unordered_map>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Assert.h"
 #include "Common/ChunkFile.h"
 #include "Common/Logging/Log.h"
 #include "Common/SPSCQueue.h"
-#include "Common/StringUtil.h"
-#include "Common/Thread.h"
 
 #include "Core/ConfigManager.h"
 #include "Core/Core.h"
@@ -396,8 +396,7 @@ std::string GetScheduledEventsSummary()
   std::sort(clone.begin(), clone.end());
   for (const Event& ev : clone)
   {
-    text += StringFromFormat("%s : %" PRIi64 " %016" PRIx64 "\n", ev.type->name->c_str(), ev.time,
-                             ev.userdata);
+    text += fmt::format("{} : {} {:016x}\n", *ev.type->name, ev.time, ev.userdata);
   }
   return text;
 }
diff --git a/Source/Core/Core/DSP/DSPAssembler.cpp b/Source/Core/Core/DSP/DSPAssembler.cpp
index 549e7df8f2..b7f1ddb666 100644
--- a/Source/Core/Core/DSP/DSPAssembler.cpp
+++ b/Source/Core/Core/DSP/DSPAssembler.cpp
@@ -17,6 +17,8 @@
 #include <utility>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/FileUtil.h"
 #include "Common/StringUtil.h"
@@ -91,7 +93,7 @@ void DSPAssembler::ShowError(AssemblerError err_code, const char* extra_info)
   if (!m_settings.force)
     m_failed = true;
 
-  std::string error = StringFromFormat("%u : %s ", m_code_line, m_cur_line.c_str());
+  std::string error = fmt::format("{} : {} ", m_code_line, m_cur_line);
   if (!extra_info)
     extra_info = "-";
 
@@ -99,12 +101,12 @@ void DSPAssembler::ShowError(AssemblerError err_code, const char* extra_info)
 
   if (m_current_param == 0)
   {
-    error += StringFromFormat("ERROR: %s Line: %u : %s\n", error_string, m_code_line, extra_info);
+    error += fmt::format("ERROR: {} Line: {} : {}\n", error_string, m_code_line, extra_info);
   }
   else
   {
-    error += StringFromFormat("ERROR: %s Line: %u Param: %d : %s\n", error_string, m_code_line,
-                              m_current_param, extra_info);
+    error += fmt::format("ERROR: {} Line: {} Param: {} : {}\n", error_string, m_code_line,
+                         m_current_param, extra_info);
   }
 
   m_last_error_str = std::move(error);
@@ -958,8 +960,8 @@ bool DSPAssembler::AssemblePass(const std::string& text, int pass)
       {
         if (m_cur_addr > params[0].val)
         {
-          std::string msg = StringFromFormat("WARNPC at 0x%04x, expected 0x%04x or less",
-                                             m_cur_addr, params[0].val);
+          const std::string msg = fmt::format("WARNPC at 0x{:04x}, expected 0x{:04x} or less",
+                                              m_cur_addr, params[0].val);
           ShowError(AssemblerError::PCOutOfRange, msg.c_str());
         }
       }
diff --git a/Source/Core/Core/DSP/DSPCodeUtil.cpp b/Source/Core/Core/DSP/DSPCodeUtil.cpp
index d71da68c14..313bda78ab 100644
--- a/Source/Core/Core/DSP/DSPCodeUtil.cpp
+++ b/Source/Core/Core/DSP/DSPCodeUtil.cpp
@@ -9,6 +9,8 @@
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/File.h"
 #include "Common/FileUtil.h"
@@ -147,7 +149,7 @@ bool SaveBinary(const std::vector<u16>& code, const std::string& filename)
 bool DumpDSPCode(const u8* code_be, int size_in_bytes, u32 crc)
 {
   const std::string root_name =
-      File::GetUserPath(D_DUMPDSP_IDX) + StringFromFormat("DSP_UC_%08X", crc);
+      File::GetUserPath(D_DUMPDSP_IDX) + fmt::format("DSP_UC_{:08X}", crc);
   const std::string binary_file = root_name + ".bin";
   const std::string text_file = root_name + ".txt";
 
diff --git a/Source/Core/Core/DSP/DSPDisassembler.cpp b/Source/Core/Core/DSP/DSPDisassembler.cpp
index d4a527ebc7..963f5fabd6 100644
--- a/Source/Core/Core/DSP/DSPDisassembler.cpp
+++ b/Source/Core/Core/DSP/DSPDisassembler.cpp
@@ -10,6 +10,8 @@
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/StringUtil.h"
@@ -73,16 +75,16 @@ std::string DSPDisassembler::DisassembleParameters(const DSPOPCTemplate& opc, u1
     {
     case P_REG:
       if (settings_.decode_registers)
-        buf += StringFromFormat("$%s", pdregname(val));
+        buf += fmt::format("${}", pdregname(val));
       else
-        buf += StringFromFormat("$%d", val);
+        buf += fmt::format("${}", val);
       break;
 
     case P_PRG:
       if (settings_.decode_registers)
-        buf += StringFromFormat("@$%s", pdregname(val));
+        buf += fmt::format("@${}", pdregname(val));
       else
-        buf += StringFromFormat("@$%d", val);
+        buf += fmt::format("@${}", val);
       break;
 
     case P_VAL:
@@ -94,22 +96,27 @@ std::string DSPDisassembler::DisassembleParameters(const DSPOPCTemplate& opc, u1
       }
       else
       {
-        buf += StringFromFormat("0x%04x", val);
+        buf += fmt::format("0x{:04x}", val);
       }
       break;
 
     case P_IMM:
       if (opc.params[j].size != 2)
       {
-        if (opc.params[j].mask == 0x003f)  // LSL, LSR, ASL, ASR
-          buf += StringFromFormat("#%d",
-                                  (val & 0x20) ? (val | 0xFFFFFFC0) : val);  // 6-bit sign extension
+        // LSL, LSR, ASL, ASR
+        if (opc.params[j].mask == 0x003f)
+        {
+          // 6-bit sign extension
+          buf += fmt::format("#{}", (val & 0x20) != 0 ? (val | 0xFFFFFFC0) : val);
+        }
         else
-          buf += StringFromFormat("#0x%02x", val);
+        {
+          buf += fmt::format("#0x{:02x}", val);
+        }
       }
       else
       {
-        buf += StringFromFormat("#0x%04x", val);
+        buf += fmt::format("#0x{:04x}", val);
       }
       break;
 
@@ -118,9 +125,9 @@ std::string DSPDisassembler::DisassembleParameters(const DSPOPCTemplate& opc, u1
         val = (u16)(s16)(s8)val;
 
       if (settings_.decode_names)
-        buf += StringFromFormat("@%s", pdname(val));
+        buf += fmt::format("@{}", pdname(val));
       else
-        buf += StringFromFormat("@0x%04x", val);
+        buf += fmt::format("@0x{:04x}", val);
       break;
 
     default:
@@ -174,7 +181,7 @@ bool DSPDisassembler::DisassembleOpcode(const u16* binbuf, u16* pc, std::string&
   // printing
 
   if (settings_.show_pc)
-    dest += StringFromFormat("%04x ", *pc);
+    dest += fmt::format("{:04x} ", *pc);
 
   u16 op2;
 
@@ -183,25 +190,25 @@ bool DSPDisassembler::DisassembleOpcode(const u16* binbuf, u16* pc, std::string&
   {
     op2 = binbuf[(*pc + 1) & 0x0fff];
     if (settings_.show_hex)
-      dest += StringFromFormat("%04x %04x ", op1, op2);
+      dest += fmt::format("{:04x} {:04x} ", op1, op2);
   }
   else
   {
     op2 = 0;
     if (settings_.show_hex)
-      dest += StringFromFormat("%04x      ", op1);
+      dest += fmt::format("{:04x}      ", op1);
   }
 
   std::string opname = opc->name;
   if (is_extended)
-    opname += StringFromFormat("%c%s", settings_.ext_separator, opc_ext->name);
+    opname += fmt::format("{}{}", settings_.ext_separator, opc_ext->name);
   if (settings_.lower_case_ops)
     std::transform(opname.begin(), opname.end(), opname.begin(), ::tolower);
 
   if (settings_.print_tabs)
-    dest += StringFromFormat("%s\t", opname.c_str());
+    dest += fmt::format("{}\t", opname);
   else
-    dest += StringFromFormat("%-12s", opname.c_str());
+    dest += fmt::format("{:<12}", opname);
 
   if (opc->param_count > 0)
     dest += DisassembleParameters(*opc, op1, op2);
diff --git a/Source/Core/Core/Debugger/Debugger_SymbolMap.cpp b/Source/Core/Core/Debugger/Debugger_SymbolMap.cpp
index 4dea4dfc32..477faba7ea 100644
--- a/Source/Core/Core/Debugger/Debugger_SymbolMap.cpp
+++ b/Source/Core/Core/Debugger/Debugger_SymbolMap.cpp
@@ -8,12 +8,13 @@
 #include <functional>
 #include <string>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/StringUtil.h"
 
 #include "Core/Core.h"
 #include "Core/PowerPC/MMU.h"
-#include "Core/PowerPC/PPCAnalyst.h"
 #include "Core/PowerPC/PPCSymbolDB.h"
 #include "Core/PowerPC/PowerPC.h"
 
@@ -81,8 +82,7 @@ bool GetCallstack(std::vector<CallstackEntry>& output)
   }
 
   CallstackEntry entry;
-  entry.Name =
-      StringFromFormat(" * %s [ LR = %08x ]\n", g_symbolDB.GetDescription(LR).c_str(), LR - 4);
+  entry.Name = fmt::format(" * {} [ LR = {:08x} ]\n", g_symbolDB.GetDescription(LR), LR - 4);
   entry.vAddress = LR - 4;
   output.push_back(entry);
 
@@ -90,7 +90,7 @@ bool GetCallstack(std::vector<CallstackEntry>& output)
     std::string func_desc = g_symbolDB.GetDescription(func_addr);
     if (func_desc.empty() || func_desc == "Invalid")
       func_desc = "(unknown)";
-    entry.Name = StringFromFormat(" * %s [ addr = %08x ]\n", func_desc.c_str(), func_addr - 4);
+    entry.Name = fmt::format(" * {} [ addr = {:08x} ]\n", func_desc, func_addr - 4);
     entry.vAddress = func_addr - 4;
     output.push_back(entry);
   });
@@ -150,7 +150,7 @@ void PrintDataBuffer(LogTypes::LOG_TYPE type, const u8* data, size_t size, const
     std::string hex_line;
     for (int i = 0; i < 16; i++)
     {
-      hex_line += StringFromFormat("%02x ", data[j++]);
+      hex_line += fmt::format("{:02x} ", data[j++]);
 
       if (j >= size)
         break;
diff --git a/Source/Core/Core/HW/DVD/FileMonitor.cpp b/Source/Core/Core/HW/DVD/FileMonitor.cpp
index 6ec4aec500..74a6122522 100644
--- a/Source/Core/Core/HW/DVD/FileMonitor.cpp
+++ b/Source/Core/Core/HW/DVD/FileMonitor.cpp
@@ -10,12 +10,13 @@
 #include <string>
 #include <unordered_set>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/Logging/LogManager.h"
 #include "Common/StringUtil.h"
 
-#include "DiscIO/Enums.h"
 #include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 
@@ -76,7 +77,7 @@ void Log(const DiscIO::Volume& volume, const DiscIO::Partition& partition, u64 o
 
   const std::string size_string = ThousandSeparate(file_info->GetSize() / 1000, 7);
   const std::string path = file_info->GetPath();
-  const std::string log_string = StringFromFormat("%s kB %s", size_string.c_str(), path.c_str());
+  const std::string log_string = fmt::format("{} kB {}", size_string, path);
   if (IsSoundFile(path))
     INFO_LOG(FILEMON, "%s", log_string.c_str());
   else
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceGecko.cpp b/Source/Core/Core/HW/EXI/EXI_DeviceGecko.cpp
index 09c7b932e1..0b31482e3f 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceGecko.cpp
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceGecko.cpp
@@ -11,10 +11,11 @@
 #include <thread>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
-#include "Common/StringUtil.h"
 #include "Common/Thread.h"
 #include "Core/Core.h"
 
@@ -66,7 +67,7 @@ void GeckoSockServer::GeckoConnectionWaiter()
   if (!server_running.IsSet())
     return;
 
-  Core::DisplayMessage(StringFromFormat("USBGecko: Listening on TCP port %u", server_port), 5000);
+  Core::DisplayMessage(fmt::format("USBGecko: Listening on TCP port {}", server_port), 5000);
 
   server.setBlocking(false);
 
diff --git a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
index db171bf378..7e004ddc92 100644
--- a/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
+++ b/Source/Core/Core/HW/EXI/EXI_DeviceMemoryCard.cpp
@@ -10,6 +10,8 @@
 #include <memory>
 #include <string>
 
+#include <fmt/format.h>
+
 #include "Common/ChunkFile.h"
 #include "Common/CommonPaths.h"
 #include "Common/CommonTypes.h"
@@ -17,8 +19,6 @@
 #include "Common/FileUtil.h"
 #include "Common/IniFile.h"
 #include "Common/Logging/Log.h"
-#include "Common/NandPaths.h"
-#include "Common/StringUtil.h"
 #include "Core/CommonTitles.h"
 #include "Core/Config/MainSettings.h"
 #include "Core/ConfigManager.h"
@@ -192,7 +192,7 @@ void CEXIMemoryCard::SetupGciFolder(u16 sizeMb)
   else
   {
     strDirectoryName = strDirectoryName + SConfig::GetDirectoryForRegion(region) + DIR_SEP +
-                       StringFromFormat("Card %c", 'A' + card_index);
+                       fmt::format("Card {}", char('A' + card_index));
   }
 
   const File::FileInfo file_info(strDirectoryName);
@@ -234,8 +234,7 @@ void CEXIMemoryCard::SetupRawMemcard(u16 sizeMb)
                                      Config::Get(Config::MAIN_MEMCARD_B_PATH);
   if (Movie::IsPlayingInput() && Movie::IsConfigSaved() && Movie::IsUsingMemcard(card_index) &&
       Movie::IsStartingFromClearSave())
-    filename =
-        File::GetUserPath(D_GCUSER_IDX) + StringFromFormat("Movie%s.raw", is_slot_a ? "A" : "B");
+    filename = File::GetUserPath(D_GCUSER_IDX) + fmt::format("Movie{}.raw", is_slot_a ? 'A' : 'B');
 
   const std::string region_dir =
       SConfig::GetDirectoryForRegion(SConfig::ToGameCubeRegion(SConfig::GetInstance().m_region));
diff --git a/Source/Core/Core/HW/GCMemcard/GCMemcardDirectory.cpp b/Source/Core/Core/HW/GCMemcard/GCMemcardDirectory.cpp
index 6e03d63f3f..9210f00d99 100644
--- a/Source/Core/Core/HW/GCMemcard/GCMemcardDirectory.cpp
+++ b/Source/Core/Core/HW/GCMemcard/GCMemcardDirectory.cpp
@@ -13,6 +13,8 @@
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Assert.h"
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
@@ -232,8 +234,7 @@ void GCMemcardDirectory::FlushThread()
     return;
   }
 
-  Common::SetCurrentThreadName(
-      StringFromFormat("Memcard %d flushing thread", m_card_index).c_str());
+  Common::SetCurrentThreadName(fmt::format("Memcard {} flushing thread", m_card_index).c_str());
 
   constexpr std::chrono::seconds flush_interval{1};
   while (true)
@@ -627,15 +628,14 @@ void GCMemcardDirectory::FlushToFile()
 
           if (gci.IsGood())
           {
-            Core::DisplayMessage(
-                StringFromFormat("Wrote save contents to %s", m_saves[i].m_filename.c_str()), 4000);
+            Core::DisplayMessage(fmt::format("Wrote save contents to {}", m_saves[i].m_filename),
+                                 4000);
           }
           else
           {
             ++errors;
-            Core::DisplayMessage(StringFromFormat("Failed to write save contents to %s",
-                                                  m_saves[i].m_filename.c_str()),
-                                 4000);
+            Core::DisplayMessage(
+                fmt::format("Failed to write save contents to {}", m_saves[i].m_filename), 4000);
             ERROR_LOG(EXPANSIONINTERFACE, "Failed to save data to %s",
                       m_saves[i].m_filename.c_str());
           }
diff --git a/Source/Core/Core/HW/GCMemcard/GCMemcardRaw.cpp b/Source/Core/Core/HW/GCMemcard/GCMemcardRaw.cpp
index 1093b10d13..628e85efc1 100644
--- a/Source/Core/Core/HW/GCMemcard/GCMemcardRaw.cpp
+++ b/Source/Core/Core/HW/GCMemcard/GCMemcardRaw.cpp
@@ -11,6 +11,8 @@
 #include <string>
 #include <thread>
 
+#include <fmt/format.h>
+
 #include "Common/ChunkFile.h"
 #include "Common/CommonPaths.h"
 #include "Common/CommonTypes.h"
@@ -127,8 +129,7 @@ void MemoryCard::FlushThread()
     return;
   }
 
-  Common::SetCurrentThreadName(
-      StringFromFormat("Memcard %d flushing thread", m_card_index).c_str());
+  Common::SetCurrentThreadName(fmt::format("Memcard {} flushing thread", m_card_index).c_str());
 
   const auto flush_interval = std::chrono::seconds(15);
 
@@ -182,17 +183,12 @@ void MemoryCard::FlushThread()
     }
     file.WriteBytes(&m_flush_buffer[0], m_memory_card_size);
 
-    if (!do_exit)
-    {
-      Core::DisplayMessage(StringFromFormat("Wrote memory card %c contents to %s",
-                                            m_card_index ? 'B' : 'A', m_filename.c_str())
-                               .c_str(),
-                           4000);
-    }
-    else
-    {
+    if (do_exit)
       return;
-    }
+
+    Core::DisplayMessage(
+        fmt::format("Wrote memory card {} contents to {}", m_card_index ? 'B' : 'A', m_filename),
+        4000);
   }
 }
 
diff --git a/Source/Core/Core/HW/SI/SI_Device.cpp b/Source/Core/Core/HW/SI/SI_Device.cpp
index 0d5eb89289..e4637709bd 100644
--- a/Source/Core/Core/HW/SI/SI_Device.cpp
+++ b/Source/Core/Core/HW/SI/SI_Device.cpp
@@ -7,9 +7,10 @@
 #include <memory>
 #include <string>
 
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
-#include "Common/StringUtil.h"
 #include "Core/HW/SI/SI_DeviceDanceMat.h"
 #include "Core/HW/SI/SI_DeviceGBA.h"
 #include "Core/HW/SI/SI_DeviceGCAdapter.h"
@@ -48,7 +49,7 @@ int ISIDevice::RunBuffer(u8* buffer, int request_length)
 
   while (num < request_length)
   {
-    temp += StringFromFormat("0x%02x ", buffer[num]);
+    temp += fmt::format("0x{:02x} ", buffer[num]);
     num++;
 
     if ((num % 8) == 0)
diff --git a/Source/Core/Core/HW/WiiSave.cpp b/Source/Core/Core/HW/WiiSave.cpp
index c15d9b8a49..8d1fae4722 100644
--- a/Source/Core/Core/HW/WiiSave.cpp
+++ b/Source/Core/Core/HW/WiiSave.cpp
@@ -22,6 +22,8 @@
 #include <utility>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Align.h"
 #include "Common/CommonTypes.h"
 #include "Common/Crypto/ec.h"
@@ -478,22 +480,22 @@ bool Import(const std::string& data_bin_path, std::function<bool()> can_overwrit
   return Copy(data_bin.get(), nand.get());
 }
 
-static bool Export(u64 tid, const std::string& export_path, IOS::HLE::Kernel* ios)
+static bool Export(u64 tid, std::string_view export_path, IOS::HLE::Kernel* ios)
 {
-  std::string path = StringFromFormat("%s/private/wii/title/%c%c%c%c/data.bin", export_path.c_str(),
-                                      static_cast<char>(tid >> 24), static_cast<char>(tid >> 16),
-                                      static_cast<char>(tid >> 8), static_cast<char>(tid));
+  const std::string path = fmt::format("{}/private/wii/title/{}{}{}{}/data.bin", export_path,
+                                       static_cast<char>(tid >> 24), static_cast<char>(tid >> 16),
+                                       static_cast<char>(tid >> 8), static_cast<char>(tid));
   return Copy(MakeNandStorage(ios->GetFS().get(), tid).get(),
               MakeDataBinStorage(&ios->GetIOSC(), path, "w+b").get());
 }
 
-bool Export(u64 tid, const std::string& export_path)
+bool Export(u64 tid, std::string_view export_path)
 {
   IOS::HLE::Kernel ios;
   return Export(tid, export_path, &ios);
 }
 
-size_t ExportAll(const std::string& export_path)
+size_t ExportAll(std::string_view export_path)
 {
   IOS::HLE::Kernel ios;
   size_t exported_save_count = 0;
diff --git a/Source/Core/Core/HW/WiiSave.h b/Source/Core/Core/HW/WiiSave.h
index cde5d938b2..d989498a94 100644
--- a/Source/Core/Core/HW/WiiSave.h
+++ b/Source/Core/Core/HW/WiiSave.h
@@ -37,7 +37,7 @@ bool Copy(Storage* source, Storage* destination);
 /// Import a save into the NAND from a .bin file.
 bool Import(const std::string& data_bin_path, std::function<bool()> can_overwrite);
 /// Export a save to a .bin file.
-bool Export(u64 tid, const std::string& export_path);
+bool Export(u64 tid, std::string_view export_path);
 /// Export all saves that are in the NAND. Returns the number of exported saves.
-size_t ExportAll(const std::string& export_path);
+size_t ExportAll(std::string_view export_path);
 }  // namespace WiiSave
diff --git a/Source/Core/Core/HW/Wiimote.cpp b/Source/Core/Core/HW/Wiimote.cpp
index 95fe6f122b..89f4c93e44 100644
--- a/Source/Core/Core/HW/Wiimote.cpp
+++ b/Source/Core/Core/HW/Wiimote.cpp
@@ -4,10 +4,10 @@
 
 #include "Core/HW/Wiimote.h"
 
+#include <fmt/format.h>
+
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
-#include "Common/Logging/Log.h"
-#include "Common/StringUtil.h"
 
 #include "Core/ConfigManager.h"
 #include "Core/Core.h"
@@ -20,7 +20,6 @@
 #include "Core/NetPlayClient.h"
 
 #include "InputCommon/ControllerEmu/ControlGroup/ControlGroup.h"
-#include "InputCommon/ControllerInterface/ControllerInterface.h"
 #include "InputCommon/InputConfig.h"
 
 // Limit the amount of wiimote connect requests, when a button is pressed in disconnected state
@@ -127,8 +126,8 @@ void Connect(unsigned int index, bool connect)
   if (bluetooth)
     bluetooth->AccessWiimoteByIndex(index)->Activate(connect);
 
-  const char* message = connect ? "Wii Remote %u connected" : "Wii Remote %u disconnected";
-  Core::DisplayMessage(StringFromFormat(message, index + 1), 3000);
+  const char* const message = connect ? "Wii Remote {} connected" : "Wii Remote {} disconnected";
+  Core::DisplayMessage(fmt::format(message, index + 1), 3000);
 }
 
 void ResetAllWiimotes()
diff --git a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
index c1f9663c7e..94c1dcc990 100644
--- a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
@@ -8,8 +8,8 @@
 #include <cassert>
 #include <memory>
 
-#include "Common/BitUtils.h"
-#include "Common/ChunkFile.h"
+#include <fmt/format.h>
+
 #include "Common/CommonTypes.h"
 #include "Common/Config/Config.h"
 #include "Common/Logging/Log.h"
@@ -236,7 +236,7 @@ Wiimote::Wiimote(const unsigned int index) : m_index(index)
 
 std::string Wiimote::GetName() const
 {
-  return StringFromFormat("Wiimote%d", 1 + m_index);
+  return fmt::format("Wiimote{}", 1 + m_index);
 }
 
 ControllerEmu::ControlGroup* Wiimote::GetWiimoteGroup(WiimoteGroup group)
diff --git a/Source/Core/Core/HotkeyManager.cpp b/Source/Core/Core/HotkeyManager.cpp
index 8f58768710..6a39e98566 100644
--- a/Source/Core/Core/HotkeyManager.cpp
+++ b/Source/Core/Core/HotkeyManager.cpp
@@ -9,6 +9,8 @@
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Common.h"
 #include "Common/CommonTypes.h"
 #include "Common/StringUtil.h"
@@ -426,12 +428,12 @@ void HotkeyManager::LoadDefaults(const ControllerInterface& ciface)
   set_key_expression(HK_FREELOOK_RESET, SHIFT + " & R");
 
   // Savestates
+  const std::string non_fmt = NON + " & `F{}`";
+  const std::string shift_fmt = SHIFT + " & `F{}`";
   for (int i = 0; i < 8; i++)
   {
-    set_key_expression(HK_LOAD_STATE_SLOT_1 + i,
-                       StringFromFormat((NON + " & `F%d`").c_str(), i + 1));
-    set_key_expression(HK_SAVE_STATE_SLOT_1 + i,
-                       StringFromFormat((SHIFT + " & `F%d`").c_str(), i + 1));
+    set_key_expression(HK_LOAD_STATE_SLOT_1 + i, fmt::format(non_fmt, i + 1));
+    set_key_expression(HK_SAVE_STATE_SLOT_1 + i, fmt::format(shift_fmt, i + 1));
   }
   set_key_expression(HK_UNDO_LOAD_STATE, NON + " & `F12`");
   set_key_expression(HK_UNDO_SAVE_STATE, SHIFT + " & `F12`");
diff --git a/Source/Core/Core/NetPlayClient.cpp b/Source/Core/Core/NetPlayClient.cpp
index e2c5731e15..af41ab3eff 100644
--- a/Source/Core/Core/NetPlayClient.cpp
+++ b/Source/Core/Core/NetPlayClient.cpp
@@ -15,6 +15,7 @@
 #include <type_traits>
 #include <vector>
 
+#include <fmt/format.h>
 #include <lzo/lzo1x.h>
 #include <mbedtls/md5.h>
 
@@ -849,7 +850,7 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
       packet >> is_slot_a >> file_count;
 
       const std::string path = File::GetUserPath(D_GCUSER_IDX) + GC_MEMCARD_NETPLAY DIR_SEP +
-                               StringFromFormat("Card %c", is_slot_a ? 'A' : 'B');
+                               fmt::format("Card {}", is_slot_a ? 'A' : 'B');
 
       if ((File::Exists(path) && !File::DeleteDirRecursively(path + DIR_SEP)) ||
           !File::CreateFullPath(path + DIR_SEP))
@@ -1235,9 +1236,8 @@ void NetPlayClient::DisplayPlayersPing()
   if (!g_ActiveConfig.bShowNetPlayPing)
     return;
 
-  OSD::AddTypedMessage(OSD::MessageType::NetPlayPing,
-                       StringFromFormat("Ping: %u", GetPlayersMaxPing()), OSD::Duration::SHORT,
-                       OSD::Color::CYAN);
+  OSD::AddTypedMessage(OSD::MessageType::NetPlayPing, fmt::format("Ping: {}", GetPlayersMaxPing()),
+                       OSD::Duration::SHORT, OSD::Color::CYAN);
 }
 
 u32 NetPlayClient::GetPlayersMaxPing() const
diff --git a/Source/Core/Core/NetPlayServer.cpp b/Source/Core/Core/NetPlayServer.cpp
index 700f9ecd48..797436976d 100644
--- a/Source/Core/Core/NetPlayServer.cpp
+++ b/Source/Core/Core/NetPlayServer.cpp
@@ -18,6 +18,7 @@
 #include <unordered_set>
 #include <vector>
 
+#include <fmt/format.h>
 #include <lzo/lzo1x.h>
 
 #include "Common/CommonPaths.h"
@@ -1064,8 +1065,8 @@ unsigned int NetPlayServer::OnData(sf::Packet& packet, Client& player)
 
     case SYNC_SAVE_DATA_FAILURE:
     {
-      m_dialog->AppendChat(StringFromFormat(Common::GetStringT("%s failed to synchronize.").c_str(),
-                                            player.name.c_str()));
+      m_dialog->AppendChat(
+          fmt::format(Common::GetStringT("{} failed to synchronize."), player.name));
       m_dialog->OnGameStartAborted();
       ChunkedDataAbort();
       m_start_pending = false;
@@ -1108,8 +1109,8 @@ unsigned int NetPlayServer::OnData(sf::Packet& packet, Client& player)
 
     case SYNC_CODES_FAILURE:
     {
-      m_dialog->AppendChat(StringFromFormat(
-          Common::GetStringT("%s failed to synchronize codes.").c_str(), player.name.c_str()));
+      m_dialog->AppendChat(
+          fmt::format(Common::GetStringT("{} failed to synchronize codes."), player.name));
       m_dialog->OnGameStartAborted();
       m_start_pending = false;
     }
@@ -1455,15 +1456,14 @@ bool NetPlayServer::SyncSaveData()
         pac << sf::Uint64{0};
       }
 
-      SendChunkedToClients(
-          std::move(pac), 1,
-          StringFromFormat("Memory Card %c Synchronization", is_slot_a ? 'A' : 'B'));
+      SendChunkedToClients(std::move(pac), 1,
+                           fmt::format("Memory Card {} Synchronization", is_slot_a ? 'A' : 'B'));
     }
     else if (SConfig::GetInstance().m_EXIDevice[i] ==
              ExpansionInterface::EXIDEVICE_MEMORYCARDFOLDER)
     {
       const std::string path = File::GetUserPath(D_GCUSER_IDX) + region + DIR_SEP +
-                               StringFromFormat("Card %c", is_slot_a ? 'A' : 'B');
+                               fmt::format("Card {}", is_slot_a ? 'A' : 'B');
 
       sf::Packet pac;
       pac << static_cast<MessageId>(NP_MSG_SYNC_SAVE_DATA);
@@ -1489,9 +1489,8 @@ bool NetPlayServer::SyncSaveData()
         pac << static_cast<u8>(0);
       }
 
-      SendChunkedToClients(
-          std::move(pac), 1,
-          StringFromFormat("GCI Folder %c Synchronization", is_slot_a ? 'A' : 'B'));
+      SendChunkedToClients(std::move(pac), 1,
+                           fmt::format("GCI Folder {} Synchronization", is_slot_a ? 'A' : 'B'));
     }
   }
 
diff --git a/Source/Core/Core/PowerPC/Interpreter/Interpreter.cpp b/Source/Core/Core/PowerPC/Interpreter/Interpreter.cpp
index f4e5959a89..2ab5ce1027 100644
--- a/Source/Core/Core/PowerPC/Interpreter/Interpreter.cpp
+++ b/Source/Core/Core/PowerPC/Interpreter/Interpreter.cpp
@@ -9,6 +9,8 @@
 #include <cinttypes>
 #include <string>
 
+#include <fmt/format.h>
+
 #include "Common/Assert.h"
 #include "Common/CommonTypes.h"
 #include "Common/GekkoDisassembler.h"
@@ -117,18 +119,16 @@ static int startTrace = 0;
 static void Trace(UGeckoInstruction& inst)
 {
   std::string regs;
-  for (int i = 0; i < 32; i++)
+  for (size_t i = 0; i < std::size(PowerPC::ppcState.gpr); i++)
   {
-    regs += StringFromFormat("r%02d: %08x ", i, PowerPC::ppcState.gpr[i]);
+    regs += fmt::format("r{:02d}: {:08x} ", i, PowerPC::ppcState.gpr[i]);
   }
 
   std::string fregs;
-  for (int i = 0; i < 32; i++)
+  for (size_t i = 0; i < std::size(PowerPC::ppcState.ps); i++)
   {
     const auto& ps = PowerPC::ppcState.ps[i];
-
-    fregs +=
-        StringFromFormat("f%02d: %08" PRIx64 " %08" PRIx64 " ", i, ps.PS0AsU64(), ps.PS1AsU64());
+    fregs += fmt::format("f{:02d}: {:08x} {:08x} ", i, ps.PS0AsU64(), ps.PS1AsU64());
   }
 
   const std::string ppc_inst = Common::GekkoDisassembler::Disassemble(inst.hex, PC);
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit.cpp b/Source/Core/Core/PowerPC/Jit64/Jit.cpp
index aa6fa49047..db5c2711a9 100644
--- a/Source/Core/Core/PowerPC/Jit64/Jit.cpp
+++ b/Source/Core/Core/PowerPC/Jit64/Jit.cpp
@@ -4,11 +4,13 @@
 
 #include "Core/PowerPC/Jit64/Jit.h"
 
-#include <disasm.h>
 #include <map>
 #include <sstream>
 #include <string>
 
+#include <disasm.h>
+#include <fmt/format.h>
+
 // for the PROFILER stuff
 #ifdef _WIN32
 #include <windows.h>
@@ -697,16 +699,16 @@ void Jit64::Trace()
   std::string fregs;
 
 #ifdef JIT_LOG_GPR
-  for (int i = 0; i < 32; i++)
+  for (size_t i = 0; i < std::size(PowerPC::ppcState.gpr); i++)
   {
-    regs += StringFromFormat("r%02d: %08x ", i, PowerPC::ppcState.gpr[i]);
+    regs += fmt::format("r{:02d}: {:08x} ", i, PowerPC::ppcState.gpr[i]);
   }
 #endif
 
 #ifdef JIT_LOG_FPR
-  for (int i = 0; i < 32; i++)
+  for (size_t i = 0; i < std::size(PowerPC::ppcState.ps); i++)
   {
-    fregs += StringFromFormat("f%02d: %016x ", i, rPS(i).PS0AsU64());
+    fregs += fmt::format("f{:02d}: {:016x} ", i, PowerPC::ppcState.ps[i].PS0AsU64());
   }
 #endif
 
diff --git a/Source/Core/Core/PowerPC/PPCAnalyst.cpp b/Source/Core/Core/PowerPC/PPCAnalyst.cpp
index 01a8224456..d56684f36a 100644
--- a/Source/Core/Core/PowerPC/PPCAnalyst.cpp
+++ b/Source/Core/Core/PowerPC/PPCAnalyst.cpp
@@ -10,11 +10,12 @@
 #include <string>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Assert.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/StringUtil.h"
-#include "Core/Config/MainSettings.h"
 #include "Core/ConfigManager.h"
 #include "Core/PowerPC/JitCommon/JitBase.h"
 #include "Core/PowerPC/MMU.h"
@@ -76,7 +77,7 @@ static u32 EvaluateBranchTarget(UGeckoInstruction instr, u32 pc)
 bool AnalyzeFunction(u32 startAddr, Common::Symbol& func, u32 max_size)
 {
   if (func.name.empty())
-    func.Rename(StringFromFormat("zz_%08x_", startAddr));
+    func.Rename(fmt::format("zz_{:08x}_", startAddr));
   if (func.analyzed)
     return true;  // No error, just already did it.
 
diff --git a/Source/Core/Core/PowerPC/PPCTables.cpp b/Source/Core/Core/PowerPC/PPCTables.cpp
index 428f6cfcaa..dd100aabac 100644
--- a/Source/Core/Core/PowerPC/PPCTables.cpp
+++ b/Source/Core/Core/PowerPC/PPCTables.cpp
@@ -11,6 +11,8 @@
 #include <cstdio>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/Assert.h"
 #include "Common/CommonTypes.h"
 #include "Common/File.h"
@@ -163,8 +165,7 @@ void LogCompiledInstructions()
 {
   static unsigned int time = 0;
 
-  File::IOFile f(StringFromFormat("%sinst_log%i.txt", File::GetUserPath(D_LOGS_IDX).c_str(), time),
-                 "w");
+  File::IOFile f(fmt::format("{}inst_log{}.txt", File::GetUserPath(D_LOGS_IDX), time), "w");
   for (size_t i = 0; i < m_numInstructions; i++)
   {
     GekkoOPInfo* pInst = m_allInstructions[i];
@@ -175,7 +176,7 @@ void LogCompiledInstructions()
     }
   }
 
-  f.Open(StringFromFormat("%sinst_not%i.txt", File::GetUserPath(D_LOGS_IDX).c_str(), time), "w");
+  f.Open(fmt::format("{}inst_not{}.txt", File::GetUserPath(D_LOGS_IDX), time), "w");
   for (size_t i = 0; i < m_numInstructions; i++)
   {
     GekkoOPInfo* pInst = m_allInstructions[i];
@@ -187,8 +188,7 @@ void LogCompiledInstructions()
   }
 
 #ifdef OPLOG
-  f.Open(StringFromFormat("%s" OP_TO_LOG "_at%i.txt", File::GetUserPath(D_LOGS_IDX).c_str(), time),
-         "w");
+  f.Open(fmt::format("{}" OP_TO_LOG "_at{}.txt", File::GetUserPath(D_LOGS_IDX), time), "w");
   for (auto& rsplocation : rsplocations)
   {
     fprintf(f.GetHandle(), OP_TO_LOG ": %08x\n", rsplocation);
diff --git a/Source/Core/Core/State.cpp b/Source/Core/Core/State.cpp
index 8a45b2f277..09d8f4ea4c 100644
--- a/Source/Core/Core/State.cpp
+++ b/Source/Core/Core/State.cpp
@@ -12,6 +12,8 @@
 #include <utility>
 #include <vector>
 
+#include <fmt/format.h>
+
 #include "Common/ChunkFile.h"
 #include "Common/CommonTypes.h"
 #include "Common/Event.h"
@@ -19,7 +21,6 @@
 #include "Common/FileUtil.h"
 #include "Common/MsgHandler.h"
 #include "Common/ScopeGuard.h"
-#include "Common/StringUtil.h"
 #include "Common/Thread.h"
 #include "Common/Timer.h"
 #include "Common/Version.h"
@@ -163,8 +164,8 @@ static void DoState(PointerWrap& p)
   p.Do(is_wii);
   if (is_wii != is_wii_currently)
   {
-    OSD::AddMessage(StringFromFormat("Cannot load a savestate created under %s mode in %s mode",
-                                     is_wii ? "Wii" : "GC", is_wii_currently ? "Wii" : "GC"),
+    OSD::AddMessage(fmt::format("Cannot load a savestate created under {} mode in {} mode",
+                                is_wii ? "Wii" : "GC", is_wii_currently ? "Wii" : "GC"),
                     OSD::Duration::NORMAL, OSD::Color::RED);
     p.SetMode(PointerWrap::MODE_MEASURE);
     return;
@@ -382,7 +383,7 @@ static void CompressAndDumpState(CompressAndDumpState_args save_args)
     f.WriteBytes(buffer_data, buffer_size);
   }
 
-  Core::DisplayMessage(StringFromFormat("Saved State to %s", filename.c_str()), 2000);
+  Core::DisplayMessage(fmt::format("Saved State to {}", filename), 2000);
   Host_UpdateMainFrame();
 }
 
@@ -477,8 +478,9 @@ static void LoadFileStateData(const std::string& filename, std::vector<u8>& ret_
 
   if (strncmp(SConfig::GetInstance().GetGameID().c_str(), header.gameID, 6))
   {
-    Core::DisplayMessage(
-        StringFromFormat("State belongs to a different game (ID %.*s)", 6, header.gameID), 2000);
+    Core::DisplayMessage(fmt::format("State belongs to a different game (ID {})",
+                                     std::string_view{header.gameID, std::size(header.gameID)}),
+                         2000);
     return;
   }
 
@@ -578,7 +580,7 @@ void LoadAs(const std::string& filename)
         {
           if (loadedSuccessfully)
           {
-            Core::DisplayMessage(StringFromFormat("Loaded state from %s", filename.c_str()), 2000);
+            Core::DisplayMessage(fmt::format("Loaded state from {}", filename), 2000);
             if (File::Exists(filename + ".dtm"))
               Movie::LoadInput(filename + ".dtm");
             else if (!Movie::IsJustStartingRecordingInputFromSaveState() &&
@@ -633,8 +635,8 @@ void Shutdown()
 
 static std::string MakeStateFilename(int number)
 {
-  return StringFromFormat("%s%s.s%02i", File::GetUserPath(D_STATESAVES_IDX).c_str(),
-                          SConfig::GetInstance().GetGameID().c_str(), number);
+  return fmt::format("{}{}.s{:02d}", File::GetUserPath(D_STATESAVES_IDX),
+                     SConfig::GetInstance().GetGameID(), number);
 }
 
 void Save(int slot, bool wait)
diff --git a/Source/Core/Core/TitleDatabase.cpp b/Source/Core/Core/TitleDatabase.cpp
index 86f9a9feae..2daeade7b1 100644
--- a/Source/Core/Core/TitleDatabase.cpp
+++ b/Source/Core/Core/TitleDatabase.cpp
@@ -12,6 +12,8 @@
 #include <unordered_map>
 #include <utility>
 
+#include <fmt/format.h>
+
 #include "Common/FileUtil.h"
 #include "Common/MsgHandler.h"
 #include "Common/StringUtil.h"
@@ -132,6 +134,6 @@ std::string TitleDatabase::Describe(const std::string& gametdb_id, DiscIO::Langu
   const std::string& title_name = GetTitleName(gametdb_id, language);
   if (title_name.empty())
     return gametdb_id;
-  return StringFromFormat("%s (%s)", title_name.c_str(), gametdb_id.c_str());
+  return fmt::format("{} ({})", title_name, gametdb_id);
 }
 }  // namespace Core