Nope, I am not. My four Buntus run as good as my Windows boxen.
Only the i7 (Win8.1) runs harder than the rest, but the C2Q (Win7) and the i3 (At my son, running Win7) are on the same level of credit as my Quad core FM1's.
My FM2 (running Lubuntu) is -unexpectedly- slightly better than my FM1's, BTW. My AM1 (Ubuntu) holds its own very well.