diff --git a/pcsx2/IPU/IPU.c b/pcsx2/IPU/IPU.c
index 8a65610158..adabc3c3e8 100644
--- a/pcsx2/IPU/IPU.c
+++ b/pcsx2/IPU/IPU.c
@@ -32,7 +32,7 @@
 #ifdef USE_IPU_SPEEDHACK
 #	define IPU_TO_INT( val )  ipu1Interrupt()
 #	define IPU_FROM_INT( val )  ipu0Interrupt()
-#	define IPU_FASTCALL
+#	define IPU_FORCEINLINE
 #else
 #	define IPU_TO_INT( val )  CPU_INT( DMAC_TO_IPU, val )
 #	define IPU_FROM_INT( val )  CPU_INT( DMAC_FROM_IPU, val )
@@ -946,7 +946,7 @@ static void ipuSETTH(u32 val) {
 ///////////////////////
 // IPU Worker Thread //
 ///////////////////////
-#define IPU_TO_INTERRUPT(dma) { \
+#define IPU_INTERRUPT(dma) { \
 	hwIntcIrq(INTC_IPU);	\
 }
 
@@ -966,7 +966,7 @@ void IPUCMD_WRITE(u32 val) {
 	switch (ipuRegs->cmd.CMD) {
 		case SCE_IPU_BCLR:
 			ipuBCLR(val);
-			IPU_TO_INTERRUPT(DMAC_TO_IPU);
+			IPU_INTERRUPT(DMAC_TO_IPU);
 			return;
 
 		case SCE_IPU_VDEC:
diff --git a/plugins/spu2ghz/xaudio2out.cpp b/plugins/spu2ghz/xaudio2out.cpp
index 192bd12403..1cda9714d1 100644
--- a/plugins/spu2ghz/xaudio2out.cpp
+++ b/plugins/spu2ghz/xaudio2out.cpp
@@ -44,6 +44,7 @@ private:
 	public:
 		SndBuffer* sndout;
 		IXAudio2SourceVoice* pSourceVoice;
+		CRITICAL_SECTION cs;
 
 	protected:
 		STDMETHOD_(void, OnVoiceProcessingPassStart) () {}
@@ -53,8 +54,10 @@ private:
 		STDMETHOD_(void, OnBufferStart) ( void* ) {}
 		STDMETHOD_(void, OnBufferEnd) ( void* context )
 		{
+			EnterCriticalSection( &cs );
+
 			// All of these checks are necessary because XAudio2 is wonky shizat.
-			if( pSourceVoice == NULL || context == NULL || sndout == NULL ) return;
+			if( pSourceVoice == NULL || context == NULL ) return;
 
 			s16* qb = (s16*)context;
 
@@ -67,6 +70,7 @@ private:
 			buf.pContext=context;
 
 			pSourceVoice->SubmitSourceBuffer( &buf );
+			LeaveCriticalSection( &cs );
 		}
 		STDMETHOD_(void, OnLoopEnd) ( void* ) {}   
 		STDMETHOD_(void, OnVoiceError) (THIS_ void* pBufferContext, HRESULT Error) { };
@@ -121,9 +125,8 @@ public:
 		wfx.nAvgBytesPerSec = SampleRate * wfx.nBlockAlign;
 		wfx.cbSize=0;
 
-		// Egh.. not sure if the initializer for these values should be before
-		// or after CreateSourceVoice.  Some drivers could do evil things to
-		// our structure whn we create the voice.
+		InitializeCriticalSection( &voiceContext.cs );
+		EnterCriticalSection( &voiceContext.cs );
 
 		//
 		// Create an XAudio2 voice to stream this wave
@@ -136,9 +139,8 @@ public:
 			return -1;
 		}
 
-		// See comment above.  Leave this redundant code in to protect against
-		// potentially stupid drivers.
 		voiceContext.pSourceVoice = pSourceVoice;
+		voiceContext.sndout = sb;
 		pSourceVoice->FlushSourceBuffers();
 		pSourceVoice->Start( 0, 0 );
 
@@ -164,34 +166,27 @@ public:
 			buf.pAudioData=(BYTE*)buf.pContext;
 			pSourceVoice->SubmitSourceBuffer( &buf );
 		}
-		voiceContext.sndout = sb;
+		LeaveCriticalSection( &voiceContext.cs );
 
 		return 0;
 	}
 
 	void Close()
 	{
-		//
+		EnterCriticalSection( &voiceContext.cs );
+
 		// Clean up?
-		// Apparently XA2 would just rather we NOT clean up...
-
-		/*if( pSourceVoice != NULL )
-		{
-			//pSourceVoice->FlushSourceBuffers();
-			//pSourceVoice->Stop( 0 );
-			//Sleep(10);	// give the engine some time to flush voices
-			//pSourceVoice->DestroyVoice();
-		}*/
-
-		//Sleep(10);	// give the engine some more time, because I don't trust it.
-
-		//
-		// Cleanup XAudio2
-		//
-
 		// All XAudio2 interfaces are released when the engine is destroyed,
 		// but being tidy never hurt.
 
+		// Actually it can hurt.  As of DXSDK Aug 2008, doing a full cleanup causes
+		// XA2 on Vista to crash.  Even if you copy/paste code directly from Microsoft.
+		// But doing no cleanup at all causes XA2 under XP to crash.  So after much trial
+		// and error we found a happy comprimise as follows:
+
+		if( pSourceVoice != NULL )
+			pSourceVoice->DestroyVoice();
+
 		if( pMasteringVoice != NULL )
 			pMasteringVoice->DestroyVoice();
 
@@ -202,7 +197,8 @@ public:
 		voiceContext.sndout = NULL;
 		voiceContext.pSourceVoice = NULL;
 		pSourceVoice = NULL;
-
+		LeaveCriticalSection( &voiceContext.cs );
+		DeleteCriticalSection( &voiceContext.cs );
 		CoUninitialize();
 	}