[jitter] hardware questions

Hello list,
we are reconfiguring our WinXP PC at the moment to speed up the fps in  
jitter. We use it basically to generate big matrixes (1920*1200) and  
process these on the GPU.
One of the bottle necks in this system seems to be loading the matrix  
on the GPU as a texture. We did a lot of tweaking in jitter to make  
this as efficient as possible. So the next step is to upgrade the  
hardware, to speed up the fps.
For this we have the following questions:
What is the best choice of CPU? Is it more important to have the  
fastest CPU's, the fastest CPU busspeed, or the size of the L2-cache?
Regarding the motherboard, is the busspeed critical? And what about  
the ammount and the speed of the memory?

We currently use a 8800 GTX 768mb graphics card, with the Asus P5B  
Deluxe wifi (busspeed 1066mhz, 4GB 667-DDR2), and a Core 2 Quad CPU  
(Q6600 4 x 2400mhz, with a busspeed of 1066mhz and 8mb L2 cache)

Hope some of you can shed some light on these matters,

Best Lucas