Xfx5770 performance lower than 9800 gt

[taha157]

core 2 duo(2.9ghz)
3 gb ram
P5QPL-AM mobo
cooler master 460 watt psu
xfx 5770 ( just upgraded from 9800gt)
vista (32 bit)
Games performance decreased instead of inceasing.
Starcraft 2 was running at around 55 fps @ 1440x900 when I have 9800gt & it is now running at 23 fps.
Crysis was running at around 30 fps high settings @1440x900 with 9800gt & now running at 18 fps.
All other games have same problem
I have reinstalled the drivers but still no improvement.
Please tell me what is the problem

 

[rolli59]

Did you use driver sweeper? http://www.guru3d.com/category/driversweeper/

 

[spentshells]

+1 driver sweeper but hey dont expect double performance. It is however a good upgrade. I have them both but I did pick up the 5770 first in my gaming PC and the 88gt in my step daughters PC.

 

[taha157]

I have installed win7 (32 bit) then reinstalled drivers. Now all games are running at max settings & about 50% improved fps compared to 9800gt.
Thanks for reply

 

[Chirag Borawake]

[Solved]..!