I'm sure that's not how it works. I have an AMD Athlon 3700+ Clawhammer but my CPU is rated at 2.5 (Overclocked a tiny bit).
Here you go, check this site, it's very accurate
http://www.systemrequirementslab.com/referrer/srl
It allows you to test your PC for a lot of current games, it also shows you the performance rating of your CPU
Regards.
DJM.