Stopping/freezing

[Donutz]

I just built a new computer but used my old graphics card and hard drive...the system is an athlon 64 K8N-E 754 socket, 3000+ processor, 2 x 512 ballistic crucial memory, 120 Gig 7200 RPM hard drive, Geforce 4 Ti 4800 SE, 550 w truepower. When I'm running games, the graphics in the games tend to freeze up for about 10 sec then it releases and i can continue playing until another freeze happens. My old graphics card never gave me any problems and all of my drivers are updated. It freezes on the same games I used to play.... I have tried taking out ram, putting it back in, defragging, turning graphics down and I haven't got a fix for it yet. The games are swat 4 demo and Raven Shield Six:3. I read some people saying about direct X 9 or Hyper threading....I know that my mother board supports dx9 and this mother board does have hypertransport technology.......