Graphics Problem (Spiking and Rainbow)

I'm asking on behalf of my SL fiance, he's experiencing extreme avatar and prim spiking. Not only is it his own AV but other peoples and even prims like houses and object spiking. It doesn't happen all the time but when it does sometimes it's so bad that he has to relog often.

Along with the spiking out, he also experiences rainbow effects at times causing objects around him to be a rainbow color.

Here are his pc specs:

WinXP Media Center Ed
Pentium D Processor
3.03 GHz
1 GB Ram
NVidia GeForce 7900 GS graphics card

And here are some pics that he took:

http://i6.photobucket.com/albums/y249/cnelson8611/screwedupforGrim2.jpg

http://i6.photobucket.com/albums/y249/cnelson8611/screwedupforGrim3.jpg

http://i6.photobucket.com/albums/y249/cnelson8611/screwedupforGrim4.jpg


Anyone else experience these problems and what can he do to get rid of them?

That mostly likely is caused by him having VBO enabled in advanced graphics. If he unchecks it it should go away.