diff --git a/Source/Core/Common/ArmFPURoundMode.cpp b/Source/Core/Common/ArmFPURoundMode.cpp
index 94ed16d279..81daf68d2f 100644
--- a/Source/Core/Common/ArmFPURoundMode.cpp
+++ b/Source/Core/Common/ArmFPURoundMode.cpp
@@ -41,10 +41,6 @@ void SetRoundMode(int mode)
   // We don't need to do anything here since SetSIMDMode is always called after calling this
 }
 
-void SetPrecisionMode(PrecisionMode mode)
-{
-}
-
 void SetSIMDMode(int rounding_mode, bool non_ieee_mode)
 {
   // When AH is disabled, FZ controls flush-to-zero for both inputs and outputs. When AH is enabled,
diff --git a/Source/Core/Common/FPURoundMode.h b/Source/Core/Common/FPURoundMode.h
index ac99478982..5fba5c9fda 100644
--- a/Source/Core/Common/FPURoundMode.h
+++ b/Source/Core/Common/FPURoundMode.h
@@ -29,8 +29,6 @@ enum PrecisionMode
 
 void SetRoundMode(int mode);
 
-void SetPrecisionMode(PrecisionMode mode);
-
 void SetSIMDMode(int rounding_mode, bool non_ieee_mode);
 
 /*
diff --git a/Source/Core/Common/GenericFPURoundMode.cpp b/Source/Core/Common/GenericFPURoundMode.cpp
index e8bbbb7e48..81b59e6d1e 100644
--- a/Source/Core/Common/GenericFPURoundMode.cpp
+++ b/Source/Core/Common/GenericFPURoundMode.cpp
@@ -11,9 +11,6 @@ namespace FPURoundMode
 void SetRoundMode(int mode)
 {
 }
-void SetPrecisionMode(PrecisionMode mode)
-{
-}
 void SetSIMDMode(int rounding_mode, bool non_ieee_mode)
 {
 }
diff --git a/Source/Core/Common/x64FPURoundMode.cpp b/Source/Core/Common/x64FPURoundMode.cpp
index a12f99efd2..9af3ec4691 100644
--- a/Source/Core/Common/x64FPURoundMode.cpp
+++ b/Source/Core/Common/x64FPURoundMode.cpp
@@ -22,11 +22,6 @@ void SetRoundMode(int mode)
   fesetround(rounding_mode_lut[mode]);
 }
 
-void SetPrecisionMode(PrecisionMode /* mode */)
-{
-  // x64 doesn't need this - fpu is done with SSE
-}
-
 void SetSIMDMode(int rounding_mode, bool non_ieee_mode)
 {
   // OR-mask for disabling FPU exceptions (bits 7-12 in the MXCSR register)
diff --git a/Source/Core/Core/Core.cpp b/Source/Core/Core/Core.cpp
index 1ec847cecc..ddda19036f 100644
--- a/Source/Core/Core/Core.cpp
+++ b/Source/Core/Core/Core.cpp
@@ -25,6 +25,7 @@
 #include "Common/CommonPaths.h"
 #include "Common/CommonTypes.h"
 #include "Common/Event.h"
+#include "Common/FPURoundMode.h"
 #include "Common/FileUtil.h"
 #include "Common/Flag.h"
 #include "Common/Logging/Log.h"
@@ -625,6 +626,7 @@ static void EmuThread(std::unique_ptr<BootParameters> boot, WindowSystemInfo wsi
     // thread, and then takes over and becomes the video thread
     Common::SetCurrentThreadName("Video thread");
     UndeclareAsCPUThread();
+    FPURoundMode::LoadDefaultSIMDState();
 
     // Spawn the CPU thread. The CPU thread will signal the event that boot is complete.
     s_cpu_thread = std::thread(cpuThreadFunc, savestate_path, delete_savestate);
diff --git a/Source/Core/Core/HW/CPU.cpp b/Source/Core/Core/HW/CPU.cpp
index b708263bfc..e12db40dde 100644
--- a/Source/Core/Core/HW/CPU.cpp
+++ b/Source/Core/Core/HW/CPU.cpp
@@ -87,6 +87,10 @@ static void ExecutePendingJobs(std::unique_lock<std::mutex>& state_lock)
 
 void Run()
 {
+  // Updating the host CPU's rounding mode must be done on the CPU thread.
+  // We can't rely on PowerPC::Init doing it, since it's called from EmuThread.
+  PowerPC::RoundingModeUpdated();
+
   std::unique_lock state_lock(s_state_change_lock);
   while (s_state != State::PowerDown)
   {
diff --git a/Source/Core/Core/PowerPC/Interpreter/Interpreter_SystemRegisters.cpp b/Source/Core/Core/PowerPC/Interpreter/Interpreter_SystemRegisters.cpp
index c9d23577b8..ae0ff724c3 100644
--- a/Source/Core/Core/PowerPC/Interpreter/Interpreter_SystemRegisters.cpp
+++ b/Source/Core/Core/PowerPC/Interpreter/Interpreter_SystemRegisters.cpp
@@ -6,7 +6,6 @@
 
 #include "Common/Assert.h"
 #include "Common/CommonTypes.h"
-#include "Common/FPURoundMode.h"
 #include "Common/Logging/Log.h"
 #include "Core/HW/GPFifo.h"
 #include "Core/HW/SystemTimers.h"
@@ -26,13 +25,10 @@ mffsx: 80036608
 mffsx: 80036650 (huh?)
 
 */
-// TODO(ector): More proper handling of SSE state.
-// That is, set rounding mode etc when entering jit code or the interpreter loop
-// Restore rounding mode when calling anything external
 
-static void FPSCRtoFPUSettings(UReg_FPSCR fp)
+static void FPSCRUpdated(UReg_FPSCR fp)
 {
-  FPURoundMode::SetRoundMode(fp.RN);
+  PowerPC::RoundingModeUpdated();
 
   if (fp.VE || fp.OE || fp.UE || fp.ZE || fp.XE)
   {
@@ -40,9 +36,6 @@ static void FPSCRtoFPUSettings(UReg_FPSCR fp)
     // fp.VE, fp.OE, fp.UE, fp.ZE, fp.XE);
     // Pokemon Colosseum does this. Gah.
   }
-
-  // Set SSE rounding mode and denormal handling
-  FPURoundMode::SetSIMDMode(fp.RN, fp.NI);
 }
 
 static void UpdateFPSCR(UReg_FPSCR* fpscr)
@@ -57,7 +50,7 @@ void Interpreter::mtfsb0x(UGeckoInstruction inst)
   u32 b = 0x80000000 >> inst.CRBD;
 
   FPSCR.Hex &= ~b;
-  FPSCRtoFPUSettings(FPSCR);
+  FPSCRUpdated(FPSCR);
 
   if (inst.Rc)
     PowerPC::ppcState.UpdateCR1();
@@ -74,7 +67,7 @@ void Interpreter::mtfsb1x(UGeckoInstruction inst)
   else
     FPSCR |= b;
 
-  FPSCRtoFPUSettings(FPSCR);
+  FPSCRUpdated(FPSCR);
 
   if (inst.Rc)
     PowerPC::ppcState.UpdateCR1();
@@ -89,7 +82,7 @@ void Interpreter::mtfsfix(UGeckoInstruction inst)
 
   FPSCR = (FPSCR.Hex & ~mask) | (imm >> (4 * field));
 
-  FPSCRtoFPUSettings(FPSCR);
+  FPSCRUpdated(FPSCR);
 
   if (inst.Rc)
     PowerPC::ppcState.UpdateCR1();
@@ -106,7 +99,7 @@ void Interpreter::mtfsfx(UGeckoInstruction inst)
   }
 
   FPSCR = (FPSCR.Hex & ~m) | (static_cast<u32>(rPS(inst.FB).PS0AsU64()) & m);
-  FPSCRtoFPUSettings(FPSCR);
+  FPSCRUpdated(FPSCR);
 
   if (inst.Rc)
     PowerPC::ppcState.UpdateCR1();
diff --git a/Source/Core/Core/PowerPC/PowerPC.cpp b/Source/Core/Core/PowerPC/PowerPC.cpp
index 4388a6ce5f..73eac23a94 100644
--- a/Source/Core/Core/PowerPC/PowerPC.cpp
+++ b/Source/Core/Core/PowerPC/PowerPC.cpp
@@ -20,6 +20,7 @@
 #include "Common/Logging/Log.h"
 
 #include "Core/ConfigManager.h"
+#include "Core/Core.h"
 #include "Core/CoreTiming.h"
 #include "Core/HW/CPU.h"
 #include "Core/HW/SystemTimers.h"
@@ -129,6 +130,7 @@ void DoState(PointerWrap& p)
 
   if (p.GetMode() == PointerWrap::MODE_READ)
   {
+    RoundingModeUpdated();
     IBATUpdated();
     DBATUpdated();
   }
@@ -180,6 +182,7 @@ static void ResetRegisters()
   }
   SetXER({});
 
+  RoundingModeUpdated();
   DBATUpdated();
   IBATUpdated();
 
@@ -246,10 +249,6 @@ CPUCore DefaultCPUCore()
 
 void Init(CPUCore cpu_core)
 {
-  // NOTE: This function runs on EmuThread, not the CPU Thread.
-  //   Changing the rounding mode has a limited effect.
-  FPURoundMode::SetPrecisionMode(FPURoundMode::PREC_53);
-
   s_invalidate_cache_thread_safe =
       CoreTiming::RegisterEvent("invalidateEmulatedCache", InvalidateCacheThreadSafe);
 
@@ -632,4 +631,13 @@ void UpdateFPRF(double dvalue)
   FPSCR.FPRF = Common::ClassifyDouble(dvalue);
 }
 
+void RoundingModeUpdated()
+{
+  // The rounding mode is separate for each thread, so this must run on the CPU thread
+  ASSERT(Core::IsCPUThread());
+
+  FPURoundMode::SetRoundMode(FPSCR.RN);
+  FPURoundMode::SetSIMDMode(FPSCR.RN, FPSCR.NI);
+}
+
 }  // namespace PowerPC
diff --git a/Source/Core/Core/PowerPC/PowerPC.h b/Source/Core/Core/PowerPC/PowerPC.h
index 34804dfb12..73919161f2 100644
--- a/Source/Core/Core/PowerPC/PowerPC.h
+++ b/Source/Core/Core/PowerPC/PowerPC.h
@@ -306,4 +306,6 @@ inline void SetXER_OV(bool value)
 
 void UpdateFPRF(double dvalue);
 
+void RoundingModeUpdated();
+
 }  // namespace PowerPC