New hardware like cpu's will interfere with wow engine and you will get fps locked @ 64 no matter what. I managed to bypass 64 fps lock on my rig on Burning Crusade expansion by settings Config.wtf for read only file and modified following lines:
SET coresDetected "8" -not working on vanilla
SET hwDetect "0"
SET processAffinityMask "20" (will force wow to use cpu core 2 and 4 out of 7 non hyperthreaded cores on a i7) - not working in vanilla wow
SET timingTestError "0" (http://wowwiki.wikia.com/wiki/CVar_timingTestError)
SET gxRefresh "240"
And yes i need and see 240 fps. Thank you