What would be the best budget card for CoD

[Orpheus]

ATI cards don't seem to be running at full clock and as of yet there's been no explanation that I'm aware of. My 5770 runs something like Call of Pripyat at 850 core clock, and CloD never goes above 400.

Until/if this is fixed, I'd go with Nvidia.

[Robotic Pope]

Nobody has said anything about power supply yet. The fact that his pc currently has only onboard graphics means its probably a store bought PC with a weak PSU.

To the OP, if this is true then you will have to add the cost of a new PSU to the price of any of the graphics cards that have been mentioned here. The ATI 5670 is probably the best you can get without upgrading the PSU, but then that probably isn't a fast enough card for Cliffs.