diff --git a/README.md b/README.md
index 9a8e5a4..b4e86c6 100644
--- a/README.md
+++ b/README.md
@@ -45,11 +45,21 @@ Include the `lib/make/msxbuild.mk` file from your Makefile.
 And override the required paths;
 * PATH_SDCC       ?= /usr/bin
 * PATH_UNIX2DOS   ?= /usr/bin
-* PATH_OPENMSX    ?= /opt/openMSX/bin/
+* PATH_OPENMSX    ?= /usr/bin
 * PATH_MSXBUILD   ?= /opt/msxbuild
 
-Then build result based compile rules see an example in; `test/ahello-m80/0module.mk`
+Then build result based compile rules see an example in; `test/ahello-m80/0module.mk`  
+When you want to see whats happening do a debug run;
 
+	debug run;
+	
+	time MB_OPENMSX_RENDERER=SDL MB_OPENMSX_THROTTLE=ON make clean assert-all
+	real    0m32.977s
+	
+	normal run;
+	
+	time make clean assert-all
+	real    0m1.938s
 
 ## Functions
 
diff --git a/lib/make/mb_openmsx.mk b/lib/make/mb_openmsx.mk
index c214f95..79b4769 100644
--- a/lib/make/mb_openmsx.mk
+++ b/lib/make/mb_openmsx.mk
@@ -7,6 +7,8 @@ MB_OPENMSX_EXTRA_MEM    ?= -ext ram4mb
 MB_OPENMSX_JOYPORTA     ?=
 MB_OPENMSX_JOYPORTB     ?=
 MB_OPENMSX_SCALE_FACTOR ?= 3
+MB_OPENMSX_THROTTLE     ?= off
+MB_OPENMSX_RENDERER     ?=
 MB_OPENMSX_ARGS = \
   -machine $(MB_OPENMSX_MACHINE) \
   -ext slotexpander -ext ide $(MB_OPENMSX_EXTRA_MEM) $(MB_OPENMSX_EXTS) \
@@ -27,7 +29,8 @@ define _mb_openmsx_run
 	SCALE_FACTOR=$(MB_OPENMSX_SCALE_FACTOR) \
 	SPEED=$(MB_OPENMSX_SPEED) \
 	SAVE_SETTINGS_ON_EXIT=off \
-	THROTTLE=off \
+	RENDERER=$(MB_OPENMSX_RENDERER) \
+	THROTTLE=$(MB_OPENMSX_THROTTLE) \
 	$(PATH_OPENMSX)/openmsx $(MB_OPENMSX_ARGS) -control stdio < $(PATH_MSXBUILD_REAL)/lib/openmsx/boot_stdio.xml
 endef