Nvm, I was reading this forum topic:http://forums.pureoverclock.com/showthread.php?threadid=8229
Even a 5970 couldn't play it very well with max settings. (And a 5970 is equal to two underclocked GTX295s in QuadSli, or roughly 4 GTX260s)
Apparently Metro 2033 is a poorly coded piece game (probably worse coding than GTA4) that has problems in all DX versions, and fps takes an even larger hit when tessellation is turned on.
It looks way worse than Crysis yet is even more hardware intensive than Crysis...long story short = bad coding, horrible optimization