HELP!! Can't use digital output for 3d graphics on x700pro

[Crescent13]

I recently got a new computer (emachines T6212), and I bought a sound blaster audigy 2 zs, 512 mb of extra ram (corsair value select 2 x 256, hasn't come in mail yet), and a x700 pro. I also got a samsung SyncMaster 730B to go with it. When I use analog (both card and monitor, without dvi-to-vga adapter), everything works fine. But when I try to use digital (dvi both card and monitor), any 3d graphics will make the screen turn black for about two seconds, and then show the input for about two seconds, and then turn black for two seconds, etc.... I tried 3d things from a chess game to half-life 2, and they all have the same result. Any help would be great! Thanks!