I have an old PIII 800MHz that I am setting up for a cab project.
I am using direct draw and noticed that if I let MAME pick a resolution automatically for say, samsho2, it chooses 640x480 and works fast enough. However, if I force the resolution to 640x480 myselft, the game slows down terribly. I can verify that in both instances the monitor's OSD reports 640x480@60 so it is not an issue of using different resolutions in each case.
What could be going on here?
Thanks