Hehehe, thats life my friend
To the sound card idea, using reduced channels didnt work. Decent sound cards (such as SB Live) take the processing of sound like GeForces do for graphics.
I have though managed to get GP3 playable. 1024x768, 25fps, several things removed from me mirrors and median track objects. runs fine at silverstone, but for some strange reason the run down to Eau Rouge is soooo jerky it takes 30 secs to get down!