Looking for 7800 Upgrade

[Cri]

Hi guys!
Which do you think´ll be the best upgrade option?
Actually i run a XFX 7800GT OC, and I´m thinking in getting one of these:
HD3850
HD3870
or
8800GT 256mb
8800GT 512mb

It should be paired with my X2 4200@2750, 1Gb Ram and a 19" - 1280x1024
Do you think my cpu will bootleneck a little bit these cards?

Thanks for your comments!

 

[MrSneis]

Cheapest would the the 3850, you'll be at 10k 3dmark06 with an 8800gt 512mb.

I would recommend the GT but they are hard to find/pricey. You'll also probably be able to SLI with your 939 board.