Thanks for all the responses.
"Is that the the i7 Mac but then just with regular video and ram?"
No. It's a 15" 2.3 g, and I've upgraded to 8g Ram. EVERYTHING other than SL runs fine. Everything, no matter how graphics intesnive. It does auto switch based on battry power, but I'm checking it on the profile and it's running the high end card. I've even tryed turning off swtiching, so it stay on the high end. No joy.
I've not run any beta viewers, if that it the question, but the v2 functions just the same as the others. Runs perfectly onces, then fails. I'm not savvy enough to mess with Open GL. I enjoy SL, but I have other things on the computer that MUST work. So I don't want to mess around too much with the core system (especially given that I don't really know what I'm doing).