diff --git a/docs/windows.txt b/docs/windows.txt
index 1cabfe24724..6ea0351f698 100644
--- a/docs/windows.txt
+++ b/docs/windows.txt
@@ -43,7 +43,13 @@ Windows performance options
 	window and all DirectDraw/Direct3D code to execute on a second thread,
 	which can improve performance on hyperthreaded and multicore systems.
 	The default is OFF (-nomultithreading).
-
+	
+-numprocessors <auto|value>
+	Specify the number of processors to use for work queues. Specifying
+	"auto" will use the value reported by the system or environment 
+	variable OSDPROCESSORS. To avoid abuse, this value is internally limited
+	to 4 times the number of processors reported by the system. 
+	The default is "auto".
 
 
 Windows video options
diff --git a/src/osd/windows/winmain.c b/src/osd/windows/winmain.c
index 735b4ba984a..0b9b25ad47a 100644
--- a/src/osd/windows/winmain.c
+++ b/src/osd/windows/winmain.c
@@ -165,6 +165,7 @@ const options_entry mame_win_options[] =
 	{ NULL,                       NULL,       OPTION_HEADER,     "WINDOWS PERFORMANCE OPTIONS" },
 	{ "priority(-15-1)",          "0",        0,                 "thread priority for the main game thread; range from -15 to 1" },
 	{ "multithreading;mt",        "0",        OPTION_BOOLEAN,    "enable multithreading; this enables rendering and blitting on a separate thread" },
+	{ "numprocessors;np",         "auto",     0,				 "number of processors; this overrides the number the system reports" },
 
 	// video options
 	{ NULL,                       NULL,       OPTION_HEADER,     "WINDOWS VIDEO OPTIONS" },
@@ -309,6 +310,7 @@ static void output_oslog(running_machine *machine, const char *buffer)
 void osd_init(running_machine *machine)
 {
 	int watchdog = options_get_int(mame_options(), WINOPTION_WATCHDOG);
+	const char *stemp;
 
 	// thread priority
 	if (!options_get_bool(mame_options(), OPTION_DEBUG))
@@ -317,6 +319,21 @@ void osd_init(running_machine *machine)
 	// ensure we get called on the way out
 	add_exit_callback(machine, osd_exit);
 
+	// get number of processors
+	stemp = options_get_string(mame_options(), WINOPTION_NUMPROCESSORS);
+
+	osd_num_processors = 0;
+
+	if (strcmp(stemp, "auto") != 0)
+	{
+		osd_num_processors = atoi(stemp);
+		if (osd_num_processors < 1)
+		{
+			mame_printf_warning("Warning: numprocessors < 1 doesn't make much sense. Assuming auto ...\n");
+			osd_num_processors = 0;
+		}
+	}
+
 	// initialize the subsystems
 	winvideo_init(machine);
 	winsound_init(machine);
diff --git a/src/osd/windows/winmain.h b/src/osd/windows/winmain.h
index 2cf5180369a..9f788ac93b8 100644
--- a/src/osd/windows/winmain.h
+++ b/src/osd/windows/winmain.h
@@ -53,6 +53,7 @@
 // performance options
 #define WINOPTION_PRIORITY				"priority"
 #define WINOPTION_MULTITHREADING		"multithreading"
+#define WINOPTION_NUMPROCESSORS			"numprocessors"
 
 // video options
 #define WINOPTION_VIDEO					"video"
@@ -131,6 +132,8 @@
 
 extern const options_entry mame_win_options[];
 
+// defined in winwork.c
+extern int osd_num_processors;
 
 
 //============================================================
diff --git a/src/osd/windows/winwork.c b/src/osd/windows/winwork.c
index b9416db39fc..7c827d3a31f 100644
--- a/src/osd/windows/winwork.c
+++ b/src/osd/windows/winwork.c
@@ -174,7 +174,11 @@ struct _osd_work_item
 	volatile INT32		done;			// is the item done?
 };
 
+//============================================================
+//  GLOBAL VARIABLES
+//============================================================
 
+int osd_num_processors = 0;
 
 //============================================================
 //  FUNCTION PROTOTYPES
@@ -677,20 +681,28 @@ void osd_work_item_release(osd_work_item *item)
 
 static int effective_num_processors(void)
 {
-	TCHAR *procsoverride;
 	SYSTEM_INFO info;
-	int numprocs = 0;
-
-	// if the OSDPROCESSORS environment variable is set, use that value if valid
-	procsoverride = _tgetenv(_T("OSDPROCESSORS"));
-	if (procsoverride != NULL && _stscanf(procsoverride, _T("%d"), &numprocs) == 1 && numprocs > 0)
-		return numprocs;
-
-	// otherwise, fetch the info from the system
+	// fetch the info from the system
 	GetSystemInfo(&info);
 
-	// max out at 4 for now since scaling above that seems to do poorly
-	return MIN(info.dwNumberOfProcessors, 4);
+	if (osd_num_processors > 0)
+	{
+		return MIN(info.dwNumberOfProcessors * 4, osd_num_processors);
+	}
+	else
+	{
+		TCHAR *procsoverride;
+		int numprocs = 0;
+
+		// if the OSDPROCESSORS environment variable is set, use that value if valid
+		procsoverride = _tgetenv(_T("OSDPROCESSORS"));
+		if (procsoverride != NULL && _stscanf(procsoverride, _T("%d"), &numprocs) == 1 && numprocs > 0)
+			// Be well behaved ...
+			return MIN(info.dwNumberOfProcessors * 4, numprocs);
+
+		// max out at 4 for now since scaling above that seems to do poorly
+		return MIN(info.dwNumberOfProcessors, 4);
+	}
 }