Seeing as how I've only been playing Shadow Dancer... This last (major/non-'u') release - I've noticed that game was just a bit faster. When I compiled that one update I had noticed it was a bit slower than the previous version -after so many frames.
Although... I have had a couple of times where I go into/run a game, and it has a black screen, and the sound is in SLOW-MO. If I hit Alt+Tab to minimize the MAME screen/window -sound resumes to full speed... But I still can't play it. Returns to slow-mo/black screen when I go back into it.
It seems like I would play a flash or java game on the internet, then MAME would be messed up (in how it runs).