diff --git a/zsnes/src/cpu/dspproc.asm b/zsnes/src/cpu/dspproc.asm
index 75ef28f2..0d34bb78 100644
--- a/zsnes/src/cpu/dspproc.asm
+++ b/zsnes/src/cpu/dspproc.asm
@@ -125,7 +125,7 @@ EXTSYM WDSPRegF5,WDSPRegF6,WDSPRegF7,WDSPRegF8,WDSPRegF9,WDSPRegFA,WDSPRegFB
 EXTSYM WDSPRegFC,WDSPRegFD,WDSPRegFE,WDSPRegFF
 EXTSYM spcBuffera,DSPMem,SoundInterpType,NoiseData,Voice0Disable
 EXTSYM cfgecho,Surround,echobuf,ENVDisable,LowPassFilterType
-EXTSYM EMUPause,AudioLogging
+EXTSYM EMUPause,AudioLogging,MMXSupport
 
 %ifdef __MSDOS__
 EXTSYM SB_alloc_dma,SB_quality_limiter,vibracard
@@ -477,18 +477,19 @@ NEWSYM conv2speed
     jnz .next
     ret
 
-EXTSYM MMXSupport
-
 NEWSYM AdjustFrequency
+      xor ebx,ebx
       mov al,[SoundInterpType]
       mov ah,[MMXSupport]
-      cmp ah,0
+      or al,al
+      je near .notgaussian
+      or ah,ah
       jne .mmx
+      cmp al,3
+      jb .mmx
       mov al,1
       mov [SoundInterpType],al
 .mmx
-      or al,al
-      je near .notgaussian
       cmp al,2
       je near .cubicspline
       ja near .fir_mmx
@@ -1902,8 +1903,8 @@ BRRDecode:
     dec byte[sampleleft]
     jnz .nextsample
 
-    cmp byte[SoundInterpType],1
-	jae .BRR_decode_ahead
+    cmp dword[DSPInterpolate],0
+	jnz .BRR_decode_ahead
 
 	cmp byte[LowPassFilterType],2
 	jle near .no_dlpf
@@ -4444,7 +4445,7 @@ NEWSYM EchoStereo
     pop edx
     pop ebx
     mov ebx,[Voice0Freq+%1*4]
-    cmp byte[SoundInterpType],0
+    cmp dword[DSPInterpolate],0
     je %%notinterpsound
     cmp byte[StereoSound],1
     je near %%EndofProcessNEnvsi
@@ -4485,7 +4486,7 @@ NEWSYM EchoStereo
     pop edx
     pop ebx
     mov ebx,[Voice0Freq+%1*4]
-    cmp byte[SoundInterpType],0
+    cmp dword[DSPInterpolate],0
     je %%notinterpsound2
     cmp byte[StereoSound],1
     je near %%EndofProcessNEnvsi
@@ -4500,7 +4501,7 @@ NEWSYM EchoStereo
     mov dword[Voice0Time+%1*4],0FFFFFFFFh
 %%ContinueGain
     mov ebx,[Voice0Freq+%1*4]
-    cmp byte[SoundInterpType],0
+    cmp dword[DSPInterpolate],0
     je %%notinterpsound3
     cmp byte[StereoSound],1
     je near %%EndofProcessNEnvsi
@@ -4626,7 +4627,7 @@ NEWSYM EchoStereo
     mov byte[UniqueSoundv],1
 %%NotUnique
 
-    cmp byte[SoundInterpType],0
+    cmp dword[DSPInterpolate],0
     je %%notinterpsound4
     cmp byte[StereoSound],1
     je %%NextSampleSi
@@ -4801,7 +4802,7 @@ NEWSYM EchoStereo
     mov [Voice0End+%1],al
     mov ebx,[Voice0Freq+%1*4]
     add dword[Voice0Ptr+%1*4],9
-    cmp byte[SoundInterpType],0
+    cmp dword[DSPInterpolate],0
     je %%notinterpsound6
     cmp byte[StereoSound],1
     je near %%NextSampleSi
diff --git a/zsnes/src/gui/guiwindp.inc b/zsnes/src/gui/guiwindp.inc
index af191263..d78abf2f 100644
--- a/zsnes/src/gui/guiwindp.inc
+++ b/zsnes/src/gui/guiwindp.inc
@@ -20,6 +20,8 @@
 
 
 
+EXTSYM VERSION_STR,placedate
+
 SECTION .text
 
 ; Window Display Routines
@@ -1742,14 +1744,20 @@ DisplayGUISound:                     ; Sound Related Options
     GUIDisplayCheckboxun 6,11,163,SoundInterpType,1,GUISoundTextE1,0
     GUIDisplayCheckboxun 6,11,173,SoundInterpType,2,GUISoundTextE2,0
 %ifndef __MSDOS__
+    cmp byte[MMXSupport],0
+    je near .no8ptinterp
     GUIDisplayCheckboxun 6,11,183,SoundInterpType,3,GUISoundTextE3,0
+.no8ptinterp
 %endif
 
     GUIDisplayTextY 6,106,158,GUISoundTextF
     GUIDisplayCheckboxun 6,111,163,LowPassFilterType,1,GUISoundTextF1,1
     GUIDisplayCheckboxun 6,111,173,LowPassFilterType,2,GUISoundTextF2,1
 %ifndef __MSDOS__
+    cmp byte[MMXSupport],0
+    je near .nohiqualityfilter
     GUIDisplayCheckboxun 6,111,183,LowPassFilterType,3,GUISoundTextF3,0
+.nohiqualityfilter
 %endif
 
     GUIDisplayBBox 6,15,61,69,69,167            ;Sampling Rate Box
@@ -3043,7 +3051,6 @@ DisplayGUIAbout:          ; Displays the About Box
 
     ;This will attach compile date onto the end of GUIGUIAboutText1
     pushad
-    EXTSYM VERSION_STR, placedate
     mov eax,GUIGUIAboutTextA1
     mov [VERSION_STR],eax
     call placedate