Here is a few that are on my system with most settings on Ultra, made just moments ago:
I have an E6600 Core 2 proc @2.8Ghz-3Ghz with an EVGA GTX 560 Ti (images pictured above) and 4 Gigs ram.
For what it is worth, I recently upgraded from my (Qty. 2) ATI 3870's running crossfire and and was happier using the 10.5 drivers than the 11.X, with the exception of map load times during the beta. In any case, on Med-low settings, I believe my system at the time produced a little better than what you are posting here. For example:
I recall seeing some info on Umbra culling and that using that command reduces graphics settings, you did not use that by chance did you? You might try backing up, them deleting your ini files and allowing the game to recreate them just for a quick test.