I don't remember when problems started, but I guess this has to do with 'recent' versions of MAME. The point is that, even though the games run silk smooth, the sound sometimes stutters for a moment every now and then. This seems to depends very much on the test computer. In my computer it's not frequent, but a friend of mine was desperate and had to resort to an old version to play games. We both have the same MAME config, so this leads to to think that maybe the problem is in the hardware. A few days ago I had an idea: what if I lower the tab one position under the advanced properties of audio devices (XP control panel). Voila! I have been testing games for hours and no hint of the problem so far. Could this be the solution? Maybe something is wrong with using motherboard audio with recent builds of MAME? Do Soundblaster uses also experience these issues?