GTS 450 Giving me horrible Performance. HELP

Well i bought a evga gts 450 a few months back and its giving me very bad performance. When i play Starcraft 2 other games, it gives me alot of lag.

Like when i play Starcraft 2, a gts 450 should give me 60 fps on ultra in the 1280 x 1024 display and 48 fps in 1920 x 1024. And THats on ULTRA settings. When i paly on low, i only get 10-15 fps, and it even dorps to 1-5 fps sometimes.

On the site canyourunit, i checked if i can run starcraft 2, and it says im way past recommended and i fill the whole bar. Also, when i go to change the settings for starcraft 2, for all the settings it suggests i put extreme, which is maxed out on everything.

I've been searching for fixes for about 2 months now and i can't figure out whats wrong. Here are my specs

Graphics Card: EVGA gts 450
CPU:AMD Phenom(tm) 9600 Quad-Core Processor (2.3 GHz Performance Rated at: 4.6 GHz)
RAM :4.0 G
OS: Windows Vista 64
PSU: 500W

I think those are sufficient to run it on atleast medium if not ultra.
if u need any more specs msg me

I've tried everything.

I
ve updated my BIOS (didn't work)
updated drivers (didn't work)
uninstalled updated drivers and used basic driver (didnt work)


Ive searched google for many other problems regarding this card, none of them fix my problem.

ive turned vsync to force off
i have cool'n'quiet off
i have it set to high performance

and many other things.


if u have had the same problem or think you can fix it pls help ASAP! i can't stand another game playing on low settings! Makes me wanna throw the game out.