To be precise, i get a constant 300fps, and that appears to be Portals fps limit (as Fraps has a maximum fps readout of 9999fps) so theres potential to go even further than 300 if Portal allowed it. With portal render depth on 9, it stays at a constant 60fps, which seems to be a new fps for that portal render depth setting.
I was only trying to say you can't get the same framerates with an 8800GT, as you said on the last page. Thats all.