Your E6700 should work fine with Vista. DX-10 is more gpu dependent.
I have a E6400 on a Gigabye 965P-DQ6 (abiet Ver 1 also) which has been overclocked to 3.2 GHz for 2 years with no problem.
I'm running with a Bus set to 400 MHz (FSB = 1600), CPU multiplier set to 8. Memory is DDR2-800 (6400) with a 1 to 1 Ratio - also @ FSB 1600
Bottom line - If you have not overclocked your CPU - Give it a try.
For Games, check out 4850 or even a 4870 (or comparable Nvidia card. Cyris is more dependent on your GPU. Your E6700 is up to the task, especially if overclocked.