diff --git a/src/jsapi.c b/src/jsapi.c
index 0fee3bd..5dcc672 100644
--- a/src/jsapi.c
+++ b/src/jsapi.c
@@ -564,7 +564,10 @@ static duk_ret_t duk_pmem(duk_context* duk)
 		s32 val = memory->persistent.data[index];
 
 		if(!duk_is_null_or_undefined(duk, 1))
+		{
 			memory->persistent.data[index] = duk_to_int(duk, 1);
+			machine->data->syncPMEM = true;
+		}
 		
 		duk_push_int(duk, val);
 
diff --git a/src/luaapi.c b/src/luaapi.c
index 7cecac9..640f608 100644
--- a/src/luaapi.c
+++ b/src/luaapi.c
@@ -1069,6 +1069,7 @@ static s32 lua_pmem(lua_State *lua)
 			if(top >= 2)
 			{
 				memory->persistent.data[index] = getLuaNumber(lua, 2);
+				machine->data->syncPMEM = true;
 			}
 
 			lua_pushinteger(lua, val);
diff --git a/src/run.c b/src/run.c
index e37d544..be053e5 100644
--- a/src/run.c
+++ b/src/run.c
@@ -93,11 +93,11 @@ static void tick(Run* run)
 
 	enum {Size = sizeof(tic_persistent)};
 
-	// TODO: remove PMEM checking...
-	if(memcmp(&run->tic->persistent, &run->persistent, Size) != 0)
+	if(run->tickData.syncPMEM)
 	{		
 		fsSaveRootFile(run->console->fs, run->saveid, &run->tic->persistent, Size, true);
 		memcpy(&run->persistent, &run->tic->persistent, Size);
+		run->tickData.syncPMEM = false;
 	}
 
 	if(run->exit)
@@ -184,6 +184,7 @@ void initRun(Run* run, Console* console, tic_mem* tic)
 			.exit = onExit,
 			.preprocessor = processDoFile,
 			.forceExit = forceExit,
+			.syncPMEM = false,
 		},
 	};
 
diff --git a/src/tic80.c b/src/tic80.c
index 90adbac..e9e1506 100644
--- a/src/tic80.c
+++ b/src/tic80.c
@@ -104,6 +104,7 @@ TIC80_API void tic80_load(tic80* tic, void* cart, s32 size)
 		tic80->tickData.start = 0;
 		tic80->tickData.freq = getFreq;
 		tic80->tickData.counter = getCounter;
+		tic80->tickData.syncPMEM = false;
 		TickCounter = 0;
 	}
 
diff --git a/src/ticapi.h b/src/ticapi.h
index 4fc66f4..0511a2d 100644
--- a/src/ticapi.h
+++ b/src/ticapi.h
@@ -58,6 +58,8 @@ typedef struct
 	u64 (*freq)();
 	u64 start;
 
+	bool syncPMEM;
+
 	void (*preprocessor)(void* data, char* dst);
 
 	void* data;
diff --git a/src/wrenapi.c b/src/wrenapi.c
index f3f935c..2d7e16e 100644
--- a/src/wrenapi.c
+++ b/src/wrenapi.c
@@ -905,6 +905,7 @@ static void wren_pmem(WrenVM* vm)
 		if(top > 2)
 		{
 			memory->persistent.data[index] = getWrenNumber(vm, 2);
+			machine->data->syncPMEM = true;
 		}
 
 		wrenSetSlotDouble(vm, 0, val);