be careful in the NVidia control panel - with AA and/or AF (i can't remember which) enabled, GP3's performance is absolutely awful... let me know if anything works - i'm sure i tried everything though, and just resorted to painting my tyres...
I had a similar problem with my Nvidia GForce card. I saw a purple line on the wheel (the hoop to be precise) and not on the tyre. The problem was due to a part oh the hoop painted in a very light silver, that my card was not able to manage. I painted that silver with a darker grey and solved. Hope this can help you. Bye
There was a fix for this not that long ago on the forums. The problem is because of misaligned bitmaps IIRC. Search button is your friend
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function. -- F.Scott Fitzgerald