One thing about those High end Nvidias is that they do get part of their high marks by cheating on performance tests. There have been quite a big cheats on their drivers to et better benchmark numbers out from 3dMark and (apparently) other softwares used to comparing Gfx cards.
See
this pdf file about findings of Futuremark people.
What Is the Performance Difference Due to These Cheats?
A test system with GeForceFX 5900 Ultra and the 44.03 drivers gets 5806 3DMarks with
3DMark03 build 320.
The new build 330 of 3DMark03 in which 44.03 drivers cannot identify 3DMark03 or the tests in
that build gets 4679 3DMarks – a 24.1% drop.
