First of all let’s reveal the default clock speeds of the XFX 6800 Ultra 512Mb

The core is clocked at 430Mhz. The memory is clocked at 1050Mhz.

This is compared against an XFX 6800 Ultra 256Mb stock-clocked at 425/1100Mhz.

This is the test bed:

The display driver settings were all left at default unless
stated in the tests.