Does the 2900xt really blow this badly?

[Truckchase!]

Here's numbers for thought. This is with a 512 MB card. The graphs are in the following order:

Mem only overclocked
GPU only overclocked
GPU and MEM overclocked

The overclock speeds for the gpu and mem, respectively, are 858/1796 (the max the CCC will allow, nearly a 15% overclock on both). Results illustrate a heavy bottleneck on the GPU vs. the memory, as was voiced by others earlier in this thread.

EDIT: Sorry, tests are @ 1600x1200 with 4x BOX AA and 16x Aniso enabled. (Vista 32bit) My system details are in the sig below, with the obvious exception of the vid card.