auron wrote on 2021-02-25, 16:47:
that behavior vaguely sounds to me like a badly running vsync, so i would try the "override directdraw refresh" option which i think was under dxdiag.
if that doesn't help the best option is to plug in a different card and see if that changes anything... i'm just curious though, what games show this behavior exactly? since you mention fmvs - i'm pretty sure that for instance the age of empires 2 intro never played all that smoothly for me from CD, even on setups newer than that game.
I've been using Virtua Cop and Atlantis: The Lost Tales as my main benchmarks for this problem since they're the easiest ones to spot it with.
Virtua Cop runs very smoothly on here with 320x240 or whatever the lowest resolution is, until the issue suddenly pops up and then the game runs very jittery for about 30 seconds and it then becomes very smooth again for a little while more. It doesn't matter what's going on in the scene, the issue triggers at totally random spots.
Now here's an example with Atlantis. I'm just sitting on one of the 360 degree panoramas, and for a bit when moving the mouse you can look around the panorama at a fairly smooth/consistent framerate. However, once the issue randomly decides to pop up, it's no longer smooth and instead quite jerky with it skipping frames. Eventually it'll go back to being smooth again, but soon the issue will just come back. It's very distracting, and as I said earlier, it doesn't matter what I'm actually doing in the game. It pops up whenever it feels like it.
I'll try looking for that option later, thanks.