Tomshardware isn't really as accurate as this. They take a few games and a 3Dmark06 where as this is actually researched and backed up with tons of proof and personal tests.
"Please don't complain to me if you think your X1950GT beats my 7900GS or whatever. I myself don't even fully agree with this list as my 7900GS overclocked beats an X1950PRO overclocked but hey these are on average."