sonic adventure dx has an annoying problem thats got probably to do with dsound acceleration. Sometimes I got it to run smoothly, but most of the time it does what you're saying. Try playing with your Dsound settings.
my copy wont even be installed icant set it up on my win xp
i installed it on my win98 and played it from that folder strange he
about perfomance write your pc specs for me it doesnt run smooth all the time in 1024*768 res eveything maxed
you'd be better off with sonic heroes, as that game doesn't suffer from this problem and is actually quite an awesome port;
As for sonic dx, I think on PC I got it running right once, but it seems to be kinda random, but based on directsound issues...
try changing the slider in the pic... set it to basic.
nah, sonic dx is really low-spec. It just has a notorious stuttering problem;
I dont know where the vsync for s3 cards are. try the "advanced" button in that window and see if you can find gfx card settings