SC2 Help

So I just got SC2 and I'm experiencing really bad Frame Rate dips. Most of the time it runs smooth at about 40-70 FPS but sometimes (not even necasarily when theres alot going on on the screen) my frame rate drops to single digits for sometimes as much as 1min. Is anyone else having this problem or know a fix.
2 Radeon 4850s
Phenom II x3 720-Fourth core unlocked and Ocd to 3.4GHZ
6GB Patriot Sector 2000Mhz
Asus Crosshair Formula IV 890FX

Graphics settings? SC2 has lots of problems with ATI cards.

maxed, but still its wierd that its droping randomly, not due to increased load

Latest Catalyst Control Center driver?

yes indeed 10.8....and for some reason its recomending medium settings....maybe for some reason it dosent recognize second core?(its a sapphire dual 4850 card)

It could be heat related turn your fans to max and see if it still happens.

nothings going above 55c so heats not the problem