Just confirmed, the new 11.3 drivers have fixed the issue with ALT - Tab, now its almost instant (there is a .3 second black screen but its nothing).
Ill update with report on any improved/decrease in performance.
but just alt-tab fix is already good
update- alt tab definitely fixed.
Seems like there is no performance gain/loss. It feels same but alt tab fix is a MAJOR fix for me
if you can get 6850 sub $150, I say go for it!
and with sandy bridge you have, you'll have high fps

. meet u in diamond xD