Isn't it the video card the one that does all the graphics processing?The only AGP systems that can use the power of an 8800GT will be those running very high clock speeds.
I'm running an Athlon 64 x2 @ 2.8GHz PCI-E and it is NOT fast enough to properly drive my 8800GT.
If I reduce my standard 8800GT clocks by 20%, it makes almost no difference to the in game performance. Reducing the clock speeds by 50% gets a big performance drop so it seems that at around 80% of its default clock speed is good enough for my A64x2 @ 2.8GHz.
If I increase the clocks by 20%, the performance difference is negligible, as in practically zero so its pointless clocking my 8800GT !
My 8800GT (standard GPU clocks of 625/1566) has been voltmodded and will run stable at 820/1952 but, for example, it makes no difference (less than 1%) in Crysis at 1360x768 res unless I use a higher res.
Sadly higher res gives lower performance, just not as low as it would have been and is still unusable.
To get more from my 8800GT, I will need to get a fast C2D system which is exactly what I am doing in the next few weeks because of this.
My intention is to get an E4500 or 8400 and clock the nads off it in an X38 motherboard