Just thought I'd add my results in here. (By the way, that Awardfabrik program does NOT work on ALL 4850s)

I have a pair of Asus 4850's that come up in GPU-z as "Prerelease" which I don't know why this is the case, but they are pretty early cards I guess.

Testing each one individually, aircooled with Thermaltake DuOrb.

Vgpu under load is 1.29v, my max 3d06 runs last night were at 875 on both cards with the same 1.29v.

Max in 3d01 Nature (my quick "does it bench" test) was 900 core on one card, and 895 on the other. I was surprised when I read the voltage (with a DMM) and kept cranking the core up 25mhz at a time and it just kept staying stable! Fun cards

http://www.techpowerup.com/gpuz/6zpv3/