Jerky Graphics in Supreme commander.

I've been having a problem with Supreme commander on Vista. It takes a long time to load, once its loaded it runs smoothly but once I move the mouse over untis or move around the screen it starts to get really jerky and stutters. My computers Windows experiance rating is a 5.0 and my computer specs are:
Intel Dual core 3.2Ghz
2GB of RAM
500GB HD
Geforce 7600 GT

So as you can see I shouldn't have any problem running this. I can't actually fin a game that makes my computer lag...except Flight Sim X and Supreme commander. 2 of the games that were designed for Vista. Anyone got any tips for laggy vista games or to speed up vista?

I hate to tell you all that SC is not that gfx hungry Its all about CPU and Ram with this game. A 7600 is more than enough to run it but this game is different then the other 99% of games just using the gfx power to run the most part of a game. Your ram is fine CPU is ok wait and see if they fix this because even top ranged PC's lag on this game for time to time the game is a CPU/RAM Monster.

Also it depends how many units are in game 250 units=some lag 250-500=alot of lag and 500+ =almost unplayable

I've tried the game on the lowest possible settings. Still have that problem. With a 7600 GT I can run anything max with AA and AF. I've been having some problems with the graphics card though and the screen repeatedly flickers from time to time unless I change the resolution or restart my PC. Maybe it is time for a new video card...I think its vista thats the problem.