Ya at 950/1ghz clock speeds, the 5850 card will be faster than the stock GTX470 in
most games. If you are talking about the latest DX11 games with Tessellation, then the Fermi architecture is faster.
Metro 2033, with tessellation and Depth of Field in Metro 2033 - GTX470 > 5870:
http://www.bjorn3d.com/read.php?cID=1899&pageID=9320
STALKER: CoP, with God Rays enabled - 470 > 5870:
http://www.bjorn3d.com/read.php?cID=1899&pageID=9321
I still think that I wouldn't side-grade from a 5850 to a GTX470. I'd rather sell the 5850 and upgrade to the 6000 series when they come out. Overclocked, the GTX470 is as fast as the GTX480 so it will still beat the 5850 OCed. The problem is it will run hotter and louder. That trade-off is not for everyone.
I am going to test out my new GTX470 against my 4890 in about a week once I come back to Canada. Primarily, I am going to compare
noise levels! My 4890 runs at 57*C @ 27% fan speed at idle and at 80*C @ 38% fan speed at load @ 920mhz clock speeds on the GPU. The thing is ATI fan speeds and NV fan speeds are not comparable. My 8800GTS 320 was quieter at 70% fan speed than the ATI is at 30% fan speed!!!!