I have two PC's with PIII I Ghz, and Geforce 4 Ti4200, and VIA 694T based chipset motherboard with 256M RAM. I used to have Voodoo 3 3000 and Voodoo 3 2000 in these machines, and VIA 693 base chipset.
With Grand Prix 3_2000, upgrading the motherboard and graphics card made little difference to the PO. Obviously GP3_2000 was not abale to use the additional memory bandwidth performance of the VIA 694T chipset, or the additional performance of the Geforce 4.
GP4 is an entirely different matter. Changing to the GEforce 4 gave a massive performance improvement and reduction in PO. It was also noticeable that changing the motherboard also gave a performance improvement.
The conclusion is therefore clear that GP4 benefits from both increased memory bandwidth on the motherboard and increased performance from the GEFORCE 4 graphics card.