bad dvd playback

[n0estoy]

i get horrible dvd playback on my system:900mhz w/ geforce ddr on detonator3 and 256mb of ram, and i know i shouldn't be cuz my older 500 mhz could play movies just fine. I get a lot of random slowdowns, as if the drive was reading ahead, and the movie just pauses for a few seconds. Then while fastforwarding, the picture doesn't update, but the movie is indeed fastforwarding. Slowdowns also happen if a quick movement happens onscreen. I use compaq dvd player (which now gives me protection errors), Intervideo WinDVD and Leadtek Winfast DVD. Any suggestions wouldl be appreciated.

[Betamax]

Is the dma for the drive switched on? Also ALthough I'm not sure if it applies to the pograms you mentioned but in the case of powerDVD it supports geforce 2 hardware acceleration. If these supprt it check that they are switched on.

[mr2000jp]

as betamax said its some settings at the software you'r using
and there is one more thing , check if the hard disk and your dvd player is connected to the same data cable
if they are try to put each alone .