Well that just sucks.
I read here something to the effect that MAME has a timer and the monitor has its own so that even if you specify the same exact refresh rate as the original game your monitor might be off by a little:
http://www.retroblast.com/Articles/RetroBlast-MAME-Monitor-Tweaks.phpHave you played with triple buffer?
According to that article, if you enable syncrefresh and triple buffer, MAME will only draw each frame at the timing of the monitor so there will be no tearing. The disadvantage is that the game will run at the speed of the monitor refresh so if a game ran at 53fps, then you will force it to run faster to stay at 60fps.
However, I suppose that if you specify a video mode at with the same refresh rate as the original game, say 60Hz, you will get the benefit of no tearing and the difference in speed (due to the monitor not running exactly at 60Hz) should be negligible.
Would you interested in giving this a try and letting us know if it worked?
Basically, just enable syncrefresh and triplebuffer and compare to your current parameters
Has anyone played with this to try to get it right?