diff --git a/include/PR/sched.h b/include/PR/sched.h
index 166a81b73..a3ce0e627 100644
--- a/include/PR/sched.h
+++ b/include/PR/sched.h
@@ -83,7 +83,7 @@ typedef struct OSScTask_s {
 typedef struct SCClient_s {
     struct SCClient_s   *next;  /* next client in the list      */
     OSMesgQueue         *msgQ;  /* where to send the frame msg  */
-    s32                 is8mb;
+    s32                 is30fps;
 } OSScClient;
 
 typedef struct {
@@ -106,7 +106,7 @@ typedef struct {
 } OSSched;
 
 void            osCreateScheduler(OSSched *s, OSThread *thread, u8 mode, u32 numFields);
-void            osScAddClient(OSSched *s, OSScClient *c, OSMesgQueue *msgQ, int is8mb);
+void            osScAddClient(OSSched *s, OSScClient *c, OSMesgQueue *msgQ, s32 is30fps);
 void            osScRemoveClient(OSSched *s, OSScClient *c);
 OSMesgQueue     *osScGetCmdQ(OSSched *s);
 
diff --git a/src/game/gunfx.c b/src/game/gunfx.c
index c79ca59e6..920b81799 100644
--- a/src/game/gunfx.c
+++ b/src/game/gunfx.c
@@ -1880,7 +1880,7 @@ void casingCreateForHand(s32 handnum, f32 ground, Mtxf *mtx)
 			}
 
 			sp5c = ((s32)((random() >> 24) * magic) >> 10) + magic;
-			f0 = (random() % sp5c) / PALUP(781250.0f);
+			f0 = (random() % sp5c) / PALUP((f32) (OS_CPU_COUNTER / 60));
 
 			newyspeed = casing->speed.y - f0 * 0.2777778f;
 
@@ -1937,7 +1937,7 @@ void casingCreateForHand(s32 handnum, f32 ground, Mtxf *mtx)
 			}
 
 			sp4c = ((s32) ((random() >> 24) * magic) >> 10) + magic;
-			f0 = (random() % sp4c) / PALUP(781250.0f);
+			f0 = (random() % sp4c) / PALUP((f32) (OS_CPU_COUNTER / 60));
 
 			newyspeed = casing->speed.y - f0 * 0.2777778f;
 
diff --git a/src/include/bss.h b/src/include/bss.h
index 3b5193478..a7c6d7217 100644
--- a/src/include/bss.h
+++ b/src/include/bss.h
@@ -5,7 +5,7 @@
 #include "types.h"
 
 extern OSThread g_MainThread;
-extern OSMesgQueue g_SchedMesgQueue;
+extern OSMesgQueue g_MainMesgQueue;
 extern OSSched g_Sched;
 extern OSViMode var8008dcc0[2];
 extern OSViMode *var8008dd60[2];
@@ -18,7 +18,7 @@ extern OSPiHandle CartRomHandle;
 extern OSPiHandle LeoDiskHandle;
 extern OSTimer var80090ab0;
 extern OSMesgQueue g_GbpakMesgQueue;
-extern OSMesg var80090ae8;
+extern OSMesg g_GbpakMesg;
 extern u8 g_Is4Mb;
 extern u32 g_VmNumTlbMisses;
 extern u32 g_VmNumPageMisses;
diff --git a/src/include/lib/joy.h b/src/include/lib/joy.h
index 8afe1da75..6ec3748da 100644
--- a/src/include/lib/joy.h
+++ b/src/include/lib/joy.h
@@ -24,7 +24,7 @@ void joy00014238(void);
 void joyDebugJoy(void);
 s32 joyStartReadData(OSMesgQueue *mq);
 void joyReadData(void);
-void joysTick(void);
+void joysHandleRetrace(void);
 void joy00014810(bool value);
 s32 joyGetNumSamples(void);
 s32 joyGetStickXOnSample(s32 samplenum, s8 contpadnum);
diff --git a/src/include/lib/sched.h b/src/include/lib/sched.h
index 8fe290e25..b81898a57 100644
--- a/src/include/lib/sched.h
+++ b/src/include/lib/sched.h
@@ -5,7 +5,7 @@
 #include "types.h"
 
 void schedSetCrashEnable2(s32 enable);
-void schedAppendTasks(OSSched *sc, OSScTask *t);
+void schedSubmitTask(OSSched *sc, OSScTask *t);
 void __scHandleRetrace(OSSched *sc);
 void __scHandleRSP(OSSched *sc);
 void __scHandleRDP(OSSched *sc);
diff --git a/src/include/lib/snd.h b/src/include/lib/snd.h
index c751e1aa6..a2e6d2194 100644
--- a/src/include/lib/snd.h
+++ b/src/include/lib/snd.h
@@ -26,7 +26,7 @@ bool snd0000fbc4(s16 arg0);
 bool seqPlay(struct seqinstance *seq, s32 tracknum);
 u16 seqGetVolume(struct seqinstance *seq);
 void seqSetVolume(struct seqinstance *seq, u16 volume);
-void snd0000fe18(void);
+void sndHandleRetrace(void);
 void snd0000fe20(void);
 void snd0000fe50(void);
 void sndTick(void);
diff --git a/src/include/lib/vi.h b/src/include/lib/vi.h
index 2b5372e76..0dfb2b71d 100644
--- a/src/include/lib/vi.h
+++ b/src/include/lib/vi.h
@@ -9,7 +9,7 @@ void viConfigureForCopyright(u16 *fb);
 void viConfigureForLegal(void);
 void viReset(s32 stagenum);
 void viBlack(bool black);
-void vi00009ed4(void);
+void viHandleRetrace(void);
 void viUpdateMode(void);
 void viShake(f32 intensity);
 void viSetMode(s32 mode);
diff --git a/src/lib/audiomgr.c b/src/lib/audiomgr.c
index c9da2ef09..382ee38e0 100644
--- a/src/lib/audiomgr.c
+++ b/src/lib/audiomgr.c
@@ -31,7 +31,7 @@ u32 var800915bc;
 u32 var800915c0;
 u32 var800915c4;
 AMAudioMgr g_AudioManager;
-OSScClient var800918d0;
+OSScClient g_AudioSchedClient;
 u32 var800918dc;
 u32 g_AmgrFreqPerTick;
 u32 var800918e4;
@@ -182,9 +182,12 @@ void amgrMain(void *arg)
 	static u32 var8005d514 = 1;
 
 #if PAL
-	osScAddClient(&g_Sched, &var800918d0, &g_AudioManager.audioFrameMsgQ, true);
+	// Receive retrace events every second retrace
+	osScAddClient(&g_Sched, &g_AudioSchedClient, &g_AudioManager.audioFrameMsgQ, true);
 #else
-	osScAddClient(&g_Sched, &var800918d0, &g_AudioManager.audioFrameMsgQ, !IS4MB());
+	// 8MB - Receive retrace events every second retrace
+	// 4MB - Receive retrace events every retrace due to smaller command buffer
+	osScAddClient(&g_Sched, &g_AudioSchedClient, &g_AudioManager.audioFrameMsgQ, !IS4MB());
 #endif
 
 	while (!done) {
@@ -246,7 +249,7 @@ void amgrHandleFrameMsg(AudioInfo *info, AudioInfo *previnfo)
 	extern u8 aspDataStart;
 
 	if (g_AmgrCurrentCmdList) {
-		schedAppendTasks(&g_Sched, g_AmgrCurrentCmdList);
+		schedSubmitTask(&g_Sched, g_AmgrCurrentCmdList);
 	}
 
 	admaBeginFrame();
diff --git a/src/lib/boot.c b/src/lib/boot.c
index e66d95f7e..8f8ef6a9d 100644
--- a/src/lib/boot.c
+++ b/src/lib/boot.c
@@ -22,12 +22,12 @@ OSThread g_RmonThread;
 OSThread g_IdleThread;
 OSThread g_MainThread;
 OSThread g_SchedThread;
-OSMesgQueue g_SchedMesgQueue;
-OSMesg var8008db48[32];
+OSMesgQueue g_MainMesgQueue;
+OSMesg g_MainMesgBuf[32];
 OSMesgQueue *g_SchedCmdQ;
 u32 var8008dbcc;
 OSSched g_Sched;
-OSScClient var8008dca8;
+OSScClient g_MainSchedClient;
 #if VERSION >= VERSION_NTSC_1_0
 u32 g_OsMemSize;
 #else
@@ -254,7 +254,7 @@ void bootCreateRmonThread(void)
 
 void bootCreateSchedThread(void)
 {
-	osCreateMesgQueue(&g_SchedMesgQueue, var8008db48, ARRAYCOUNT(var8008db48));
+	osCreateMesgQueue(&g_MainMesgQueue, g_MainMesgBuf, ARRAYCOUNT(g_MainMesgBuf));
 
 	if (osTvType == OS_TV_MPAL) {
 		osCreateScheduler(&g_Sched, &g_SchedThread, OS_VI_MPAL_LAN1, 1);
@@ -262,7 +262,7 @@ void bootCreateSchedThread(void)
 		osCreateScheduler(&g_Sched, &g_SchedThread, OS_VI_NTSC_LAN1, 1);
 	}
 
-	osScAddClient(&g_Sched, &var8008dca8, &g_SchedMesgQueue, 0);
+	osScAddClient(&g_Sched, &g_MainSchedClient, &g_MainMesgQueue, false);
 	g_SchedCmdQ = osScGetCmdQ(&g_Sched);
 }
 
diff --git a/src/lib/joy.c b/src/lib/joy.c
index 03d30ce67..75521ecf3 100644
--- a/src/lib/joy.c
+++ b/src/lib/joy.c
@@ -34,14 +34,14 @@
 struct joydata g_JoyData[2];
 s32 g_JoyDisableCooldown[4];
 OSMesgQueue g_PiMesgQueue;
-OSMesg var80099e90[10];
-OSMesg var80099eb8[2];
+OSMesg g_PiMesgBuf[10];
+OSMesg g_JoyStopCyclicPollingMesgBuf[1];
 OSMesgQueue g_JoyStopCyclicPollingMesgQueue;
-OSMesg var80099ed8[2];
+OSMesg g_JoyStopCyclicPollingDoneMesgBuf[1];
 OSMesgQueue g_JoyStopCyclicPollingDoneMesgQueue;
-OSMesg var80099ef8[2];
+OSMesg g_JoyStartCyclicPollingMesgBuf[1];
 OSMesgQueue g_JoyStartCyclicPollingMesgQueue;
-OSMesg var80099f18[2];
+OSMesg g_JoyStartCyclicPollingDoneMesgBuf[1];
 OSMesgQueue g_JoyStartCyclicPollingDoneMesgQueue;
 OSContStatus var80099f38[4];
 #if VERSION >= VERSION_NTSC_1_0
@@ -279,11 +279,11 @@ void joyInit(void)
 	s32 i;
 	s32 j;
 
-	osCreateMesgQueue(&g_JoyStopCyclicPollingMesgQueue, var80099eb8, 1);
-	osCreateMesgQueue(&g_JoyStopCyclicPollingDoneMesgQueue, var80099ed8, 1);
-	osCreateMesgQueue(&g_JoyStartCyclicPollingMesgQueue, var80099ef8, 1);
-	osCreateMesgQueue(&g_JoyStartCyclicPollingDoneMesgQueue, var80099f18, 1);
-	osCreateMesgQueue(&g_PiMesgQueue, var80099e90, ARRAYCOUNT(var80099e90));
+	osCreateMesgQueue(&g_JoyStopCyclicPollingMesgQueue, g_JoyStopCyclicPollingMesgBuf, ARRAYCOUNT(g_JoyStopCyclicPollingMesgBuf));
+	osCreateMesgQueue(&g_JoyStopCyclicPollingDoneMesgQueue, g_JoyStopCyclicPollingDoneMesgBuf, ARRAYCOUNT(g_JoyStopCyclicPollingDoneMesgBuf));
+	osCreateMesgQueue(&g_JoyStartCyclicPollingMesgQueue, g_JoyStartCyclicPollingMesgBuf, ARRAYCOUNT(g_JoyStartCyclicPollingMesgBuf));
+	osCreateMesgQueue(&g_JoyStartCyclicPollingDoneMesgQueue, g_JoyStartCyclicPollingDoneMesgBuf, ARRAYCOUNT(g_JoyStartCyclicPollingDoneMesgBuf));
+	osCreateMesgQueue(&g_PiMesgQueue, g_PiMesgBuf, ARRAYCOUNT(g_PiMesgBuf));
 
 	osSetEventMesg(OS_EVENT_SI, &g_PiMesgQueue, NULL);
 
@@ -601,7 +601,7 @@ void joyReadData(void)
 	g_JoyData[0].nextsecondlast = (g_JoyData[0].nextlast + 19) % 20;
 }
 
-void joysTick(void)
+void joysHandleRetrace(void)
 {
 	OSMesg msg;
 	s8 i;
@@ -984,7 +984,7 @@ void joyDestroy(void)
 {
 	s32 i;
 
-	osCreateMesgQueue(&g_PiMesgQueue, var80099e90, ARRAYCOUNT(var80099e90));
+	osCreateMesgQueue(&g_PiMesgQueue, g_PiMesgBuf, ARRAYCOUNT(g_PiMesgBuf));
 	osSetEventMesg(OS_EVENT_SI, &g_PiMesgQueue, 0);
 
 	for (i = 0; i < 4; i++) {
diff --git a/src/lib/main.c b/src/lib/main.c
index 4bafc03dc..2d7b4b60e 100644
--- a/src/lib/main.c
+++ b/src/lib/main.c
@@ -345,7 +345,7 @@ void mainInit(void)
 
 	// Wait a bit, reset the controllers and wait a bit more
 	for (i = 0; i < 4; i++) {
-		osSetTimer(&timer, 781250 * 6, 0, &queue, &msg);
+		osSetTimer(&timer, OS_CPU_COUNTER / 60 * 6, 0, &queue, &msg);
 		osRecvMesg(&queue, &msg, OS_MESG_BLOCK);
 
 		if (i == 1) {
@@ -485,18 +485,18 @@ void mainInit(void)
 		g_RdpOutBufferStart = texture;
 		g_RdpOutBufferEnd = texture + 0x400; // 0x800 bytes, because texture is u16
 
-		while (osRecvMesg(&g_SchedMesgQueue, &receivedmsg, OS_MESG_NOBLOCK) == 0) {
+		while (osRecvMesg(&g_MainMesgQueue, &receivedmsg, OS_MESG_NOBLOCK) == 0) {
 			// empty
 		}
 
 		j = 0;
 
 		while (j < 6) {
-			osRecvMesg(&g_SchedMesgQueue, &receivedmsg, OS_MESG_BLOCK);
+			osRecvMesg(&g_MainMesgQueue, &receivedmsg, OS_MESG_BLOCK);
 
 			i = (s32) &scdonemsg;
 
-			if (*(s16 *) receivedmsg == 1) {
+			if (*(s16 *) receivedmsg == OS_SC_RETRACE_MSG) {
 				viUpdateMode();
 				rdpCreateTask(var8005dcc8, var8005dcf0, 0, (void *) i);
 				j++;
@@ -612,18 +612,18 @@ void mainInit(void)
 		g_RdpOutBufferStart = texture;
 		g_RdpOutBufferEnd = texture + 0x400; // 0x800 bytes, because texture is u16
 
-		while (osRecvMesg(&g_SchedMesgQueue, &receivedmsg, OS_MESG_NOBLOCK) == 0) {
+		while (osRecvMesg(&g_MainMesgQueue, &receivedmsg, OS_MESG_NOBLOCK) == 0) {
 			if (i);
 		}
 
 		i = 0;
 
 		while (i < 6) {
-			osRecvMesg(&g_SchedMesgQueue, &receivedmsg, OS_MESG_BLOCK);
+			osRecvMesg(&g_MainMesgQueue, &receivedmsg, OS_MESG_BLOCK);
 
 			j = (s32) &scdonemsg;
 
-			if (*(s16 *) receivedmsg == 1) {
+			if (*(s16 *) receivedmsg == OS_SC_RETRACE_MSG) {
 				viUpdateMode();
 				rdpCreateTask(var8005dcc8, var8005dcf0, 0, (void *) j);
 				i++;
@@ -919,9 +919,9 @@ glabel mainInit
 /*     dd8c:	0c00273c */ 	jal	viConfigureForCopyright
 /*     dd90:	02202025 */ 	or	$a0,$s1,$zero
 /*     dd94:	3c018006 */ 	lui	$at,%hi(g_RdpOutBufferStart)
-/*     dd98:	3c118009 */ 	lui	$s1,%hi(g_SchedMesgQueue)
+/*     dd98:	3c118009 */ 	lui	$s1,%hi(g_MainMesgQueue)
 /*     dd9c:	ac321554 */ 	sw	$s2,%lo(g_RdpOutBufferStart)($at)
-/*     dda0:	26310160 */ 	addiu	$s1,$s1,%lo(g_SchedMesgQueue)
+/*     dda0:	26310160 */ 	addiu	$s1,$s1,%lo(g_MainMesgQueue)
 /*     dda4:	3c018006 */ 	lui	$at,%hi(g_RdpOutBufferEnd)
 /*     dda8:	264c0800 */ 	addiu	$t4,$s2,0x800
 /*     ddac:	ac2c1550 */ 	sw	$t4,%lo(g_RdpOutBufferEnd)($at)
@@ -1346,14 +1346,14 @@ void mainLoop(void)
 		frametimeCalculate();
 		profileReset();
 
-		while (osRecvMesg(&g_SchedMesgQueue, &msg, OS_MESG_NOBLOCK) != -1) {
+		while (osRecvMesg(&g_MainMesgQueue, &msg, OS_MESG_NOBLOCK) != -1) {
 			// empty
 		}
 
 		while (g_MainChangeToStageNum < 0 || g_MainNumGfxTasks != 0) {
 			s32 cycles;
 
-			osRecvMesg(&g_SchedMesgQueue, &msg, OS_MESG_BLOCK);
+			osRecvMesg(&g_MainMesgQueue, &msg, OS_MESG_BLOCK);
 
 #if VERSION < VERSION_NTSC_1_0
 			bootCheckStackOverflow();
diff --git a/src/lib/rdp.c b/src/lib/rdp.c
index 59db11fde..d4587d66b 100644
--- a/src/lib/rdp.c
+++ b/src/lib/rdp.c
@@ -99,12 +99,12 @@ void rdpCreateTask(Gfx *gdlstart, Gfx *gdlend, u32 arg2, void *msg)
 
 	sctask->next = NULL;
 	sctask->flags = OS_SC_NEEDS_RSP | OS_SC_NEEDS_RDP | OS_SC_LAST_TASK | OS_SC_SWAPBUFFER;
-	sctask->msgQ = &g_SchedMesgQueue;
+	sctask->msgQ = &g_MainMesgQueue;
 	sctask->msg = msg;
 	sctask->framebuffer = g_RdpCurTask->framebuffer;
 
 	osWritebackDCacheAll();
-	schedAppendTasks(&g_Sched, sctask);
+	schedSubmitTask(&g_Sched, sctask);
 
 	// Swap g_RdpCurTask
 	g_RdpCurTask = (struct rdptask *)((uintptr_t) g_RdpCurTask ^ (uintptr_t) &g_RdpTaskA ^ (uintptr_t) &g_RdpTaskB);
diff --git a/src/lib/sched.c b/src/lib/sched.c
index c089cd2c4..e0feac2a4 100644
--- a/src/lib/sched.c
+++ b/src/lib/sched.c
@@ -177,14 +177,14 @@ void osCreateScheduler(OSSched *sc, OSThread *thread, u8 mode, u32 numFields)
 	osStartThread(sc->thread);
 }
 
-void osScAddClient(OSSched *sc, OSScClient *c, OSMesgQueue *msgQ, int is8mb)
+void osScAddClient(OSSched *sc, OSScClient *c, OSMesgQueue *msgQ, bool is30fps)
 {
 	OSIntMask mask;
 
 	mask = osSetIntMask(1);
 
 	c->msgQ = msgQ;
-	c->is8mb = is8mb;
+	c->is30fps = is30fps;
 	c->next = sc->clientList;
 	sc->clientList = c;
 
@@ -243,18 +243,29 @@ void __scMain(void *arg)
 
 		switch ((int) msg) {
 		case VIDEO_MSG:
+			/**
+			 * The freeze bit is set when a VI swap is pending, and unset here
+			 * when the swap is completed. It prevents the scheduler from
+			 * executing another graphics task during a VI swap.
+			 */
 			if (osViGetCurrentFramebuffer() == osViGetNextFramebuffer()) {
-				osDpSetStatus(DPC_STATUS_FLUSH);
+				osDpSetStatus(DPC_CLR_FREEZE);
 			}
 
 			__scHandleRetrace(sc);
 			__scHandleTasks(sc);
 			break;
+
 		case RSP_DONE_MSG:
 			__scHandleRSP(sc);
 			break;
+
 		case RDP_DONE_MSG:
-			osDpSetStatus(DPC_STATUS_START_GCLK);
+			/**
+			 * The RDP has completed a graphics task. Set the freeze bit so the
+			 * scheduler doesn't executing another task until the swap is done.
+			 */
+			osDpSetStatus(DPC_SET_FREEZE);
 			__scHandleRDP(sc);
 			__scHandleTasks(sc);
 			break;
@@ -262,7 +273,16 @@ void __scMain(void *arg)
 	}
 }
 
-void schedAppendTasks(OSSched *sc, OSScTask *t)
+/**
+ * Nintendo's sheduler accepts tasks on a "command" message queue.
+ * This isn't used here.
+ *
+ * In PD, the main and audio threads submit tasks by calling this function
+ * instead. It temporarily increases the calling thread's priority above the
+ * scheduler, adds the task to the linked list directly and attempts to execute
+ * it. This is faster than the queue method because it avoids switching threads.
+ */
+void schedSubmitTask(OSSched *sc, OSScTask *t)
 {
 	s32 state;
 	OSScTask *sp = 0;
@@ -274,6 +294,13 @@ void schedAppendTasks(OSSched *sc, OSScTask *t)
 	__scAppendList(sc, t);
 
 	if (sc->doAudio && sc->curRSPTask) {
+		/**
+		 * Preempt the running gfx task.  Note: if the RSP
+		 * component of the graphics task has finished, but the
+		 * RDP component is still running, we can start an audio
+		 * task which will freeze the RDP (and save the RDP cmd
+		 * FIFO) while the audio RSP code is running.
+		 */
 		__scYield(sc);
 	} else {
 		state = ((sc->curRSPTask == 0) << 1) | (sc->curRDPTask == 0);
@@ -317,11 +344,11 @@ void __scHandleRetrace(OSSched *sc)
 #endif
 
 	if (!g_Resetting) {
-		vi00009ed4();
+		viHandleRetrace();
 	}
 
-	joysTick();
-	snd0000fe18();
+	joysHandleRetrace();
+	sndHandleRetrace();
 	schedRenderCrashPeriodically(sc->frameCount);
 }
 
@@ -341,20 +368,16 @@ void __scHandleTasks(OSSched *sc)
 	profileTick();
 
 	/**
-	 * Read the task command queue and schedule tasks
+	 * This is default scheduler code. In PD, clients pass tasks to the
+	 * scheduler using schedSubmitTask. Nothing writes to the cmdQ in PD
+	 * so the condition in this loop never passes.
 	 */
 	while (osRecvMesg(&sc->cmdQ, (OSMesg*)&rspTask, OS_MESG_NOBLOCK) != -1) {
 		__scAppendList(sc, rspTask);
 	}
 
 	if (sc->doAudio && sc->curRSPTask) {
-		/**
-		 * Preempt the running gfx task.  Note: if the RSP
-		 * component of the graphics task has finished, but the
-		 * RDP component is still running, we can start an audio
-		 * task which will freeze the RDP (and save the RDP cmd
-		 * FIFO) while the audio RSP code is running.
-		 */
+		// This is unreachable because no tasks are submitted above
 		__scYield(sc);
 	} else {
 		state = ((sc->curRSPTask == 0) << 1) | (sc->curRDPTask == 0);
@@ -370,7 +393,7 @@ void __scHandleTasks(OSSched *sc)
 	 * build the list in overrun case)
 	 */
 	for (client = sc->clientList; client != 0; client = client->next) {
-		if ((*((s32*)client + 2) == 0) || ((sc->frameCount & 1) == 0)) {
+		if (!client->is30fps || (sc->frameCount & 1) == 0) {
 			osSendMesg(client->msgQ, (OSMesg) &sc->retraceMsg, OS_MESG_NOBLOCK);
 		}
 	}
@@ -575,6 +598,9 @@ void __scHandleRDP(OSSched *sc)
 /**
  * __scTaskReady checks to see if the graphics task is able to run
  * based on the current state of the RCP.
+ *
+ * PD adds the freeze bit check to avoid executing graphics tasks on the RDP
+ * when there is already a VI swap pending.
  */
 OSScTask *__scTaskReady(OSScTask *t)
 {
@@ -602,7 +628,7 @@ OSScTask *__scTaskReady(OSScTask *t)
 s32 __scTaskComplete(OSSched *sc, OSScTask *t)
 {
 	if ((t->state & OS_SC_RCP_MASK) == 0) {
-		if (t->list.t.type == 1
+		if (t->list.t.type == M_GFXTASK
 				&& (t->flags & OS_SC_SWAPBUFFER)
 				&& (t->flags & OS_SC_LAST_TASK)) {
 			if (g_SchedIsFirstTask) {
@@ -619,7 +645,7 @@ s32 __scTaskComplete(OSSched *sc, OSScTask *t)
 						|| var8008dd60[1 - var8005ce74]->fldRegs[1].yScale != var8008dcc0[1 - var8005ce74].fldRegs[1].yScale
 						|| var8008dd60[1 - var8005ce74]->fldRegs[0].origin != var8008dcc0[1 - var8005ce74].fldRegs[0].origin
 						|| var8008dd60[1 - var8005ce74]->fldRegs[1].origin != var8008dcc0[1 - var8005ce74].fldRegs[1].origin) {
-					s32 mask = osSetIntMask(0x80401);
+					s32 mask = osSetIntMask(OS_IM_VI);
 
 					*var8008dd60[1 - var8005ce74] = var8008dcc0[1 - var8005ce74];
 
@@ -681,6 +707,13 @@ void __scAppendList(OSSched *sc, OSScTask *t)
 	t->state = t->flags & OS_SC_RCP_MASK;
 }
 
+/**
+ * Execute a task on the RCP.
+ *
+ * Audio tasks use the RSP only, while graphics tasks use both the RSP and RDP.
+ * Graphics tasks commonly finish the RSP work before the RDP work, in which
+ * case the RSP can be given an audio task while the graphics task is completing.
+ */
 void __scExec(OSSched *sc, OSScTask *sp, OSScTask *dp)
 {
 	if (sp) {
@@ -688,8 +721,9 @@ void __scExec(OSSched *sc, OSScTask *sp, OSScTask *dp)
 			osWritebackDCacheAll();
 		}
 
+		// Clear RDP timing counters for graphics tasks, unless they're being resumed
 		if (sp->list.t.type != M_AUDTASK && (sp->state & OS_SC_YIELD) == 0) {
-			osDpSetStatus(DPC_STATUS_CMD_BUSY | DPC_STATUS_CBUF_READY | DPC_STATUS_DMA_BUSY | DPC_STATUS_END_VALID);
+			osDpSetStatus(DPC_CLR_TMEM_CTR | DPC_CLR_PIPE_CTR | DPC_CLR_CMD_CTR | DPC_CLR_CLOCK_CTR);
 		}
 
 		if (sp->list.t.type == M_AUDTASK) {
@@ -723,6 +757,13 @@ bool schedIsCurTaskAudio(OSSched *sc)
 }
 #endif
 
+/**
+ * Tell the RSP to pause the currently executing graphics task.
+ * The RSP will pause it shortly and __scHandleRSP will be called.
+ *
+ * Graphics tasks are yielded so an audio task can take priority.
+ * The graphics task is resumed afterwards.
+ */
 void __scYield(OSSched *sc)
 {
 	if (sc->curRSPTask->list.t.type == M_GFXTASK) {
diff --git a/src/lib/snd.c b/src/lib/snd.c
index b8674bc34..12e77e21c 100644
--- a/src/lib/snd.c
+++ b/src/lib/snd.c
@@ -1679,7 +1679,7 @@ void seqSetVolume(struct seqinstance *seq, u16 volume)
 	}
 }
 
-void snd0000fe18(void)
+void sndHandleRetrace(void)
 {
 	// empty
 }
diff --git a/src/lib/ultra/io/controller.c b/src/lib/ultra/io/controller.c
index 73b36b25d..157d6edbf 100644
--- a/src/lib/ultra/io/controller.c
+++ b/src/lib/ultra/io/controller.c
@@ -34,9 +34,9 @@ s32 osContInit(OSMesgQueue *mq, u8 *bitpattern, OSContStatus *data)
 	__osContInitialized = TRUE;
 	t = osGetTime();
 
-	if (t < 23437500) {
+	if (t < OS_CPU_COUNTER / 2) {
 		osCreateMesgQueue(&timerMesgQueue, &dummy, 1);
-		osSetTimer(&mytimer, 23437500 - t, 0, &timerMesgQueue, &dummy);
+		osSetTimer(&mytimer, OS_CPU_COUNTER / 2 - t, 0, &timerMesgQueue, &dummy);
 		osRecvMesg(&timerMesgQueue, &dummy, OS_MESG_BLOCK);
 	}
 
diff --git a/src/lib/ultra/io/gbpakinit.c b/src/lib/ultra/io/gbpakinit.c
index 454ad8ef2..94b783f16 100644
--- a/src/lib/ultra/io/gbpakinit.c
+++ b/src/lib/ultra/io/gbpakinit.c
@@ -4,7 +4,7 @@
 
 OSTimer var80090ab0;
 OSMesgQueue g_GbpakMesgQueue;
-OSMesg var80090ae8;
+OSMesg g_GbpakMesg;
 
 s32 osGbpakInit(OSMesgQueue *queue, OSPfs *pfs, int channel)
 {
@@ -76,17 +76,17 @@ s32 osGbpakInit(OSMesgQueue *queue, OSPfs *pfs, int channel)
 		return ret;
 	}
 
-	osCreateMesgQueue(&g_GbpakMesgQueue, &var80090ae8, 1);
-	osSetTimer(&var80090ab0, 937500, 0, &g_GbpakMesgQueue, &var80090ae8);
+	osCreateMesgQueue(&g_GbpakMesgQueue, &g_GbpakMesg, 1);
+	osSetTimer(&var80090ab0, OS_CPU_COUNTER / 50, 0, &g_GbpakMesgQueue, &g_GbpakMesg);
 	osRecvMesg(&g_GbpakMesgQueue, 0, OS_MESG_BLOCK);
 
 	pfs->queue = queue;
-	pfs->status = 0x10;
+	pfs->status = PFS_GBPAK_INITIALIZED;
 	pfs->channel = channel;
-	pfs->activebank = 0x84;
-	pfs->banks = 0xff;
-	pfs->version = 0xff;
-	pfs->dir_size = 0xff;
+	pfs->activebank = 132;
+	pfs->banks = 255;
+	pfs->version = 255;
+	pfs->dir_size = 255;
 
 	return 0;
 }
diff --git a/src/lib/ultra/io/gbpakpower.c b/src/lib/ultra/io/gbpakpower.c
index 3fdddac08..055a2dd11 100644
--- a/src/lib/ultra/io/gbpakpower.c
+++ b/src/lib/ultra/io/gbpakpower.c
@@ -4,7 +4,7 @@
 
 extern OSTimer var80090ab0;
 extern OSMesgQueue g_GbpakMesgQueue;
-extern OSMesg var80090ae8;
+extern OSMesg g_GbpakMesg;
 
 s32 osGbpakPower(OSPfs *pfs, s32 flag)
 {
@@ -31,7 +31,7 @@ s32 osGbpakPower(OSPfs *pfs, s32 flag)
 	}
 
 	if (flag != OS_GBPAK_POWER_OFF) {
-		osSetTimer(&var80090ab0, 937500, 0, &g_GbpakMesgQueue, &var80090ae8);
+		osSetTimer(&var80090ab0, OS_CPU_COUNTER / 50, 0, &g_GbpakMesgQueue, &g_GbpakMesg);
 		osRecvMesg(&g_GbpakMesgQueue, NULL, OS_MESG_BLOCK);
 	}
 
diff --git a/src/lib/vi.c b/src/lib/vi.c
index cb121c28d..fc8a1543b 100644
--- a/src/lib/vi.c
+++ b/src/lib/vi.c
@@ -258,7 +258,7 @@ void viBlack(bool black)
 	g_ViUnblackTimer = black;
 }
 
-void vi00009ed4(void)
+void viHandleRetrace(void)
 {
 	s32 prevmask;
 	s32 offset;