Opteron 6212 cores:8 Kernen 2,8 GHz clock speed and 3,7 GHz Turbo
Opteron 6238 cores:12 Kernen and 2,5 GHz clock speed . turbo is 3,1 GHz on all cores and the single turbo is 3,3 GHz
Opteron 6274 cores:12 clock: 2,2 GHz and turbo is 2,8 GHZ single core turbo is 3,2 GHz.
Opteron 6282 SE cores:16 clock: 2,5 GHz Turbo 3,1 GHz single threat turbo: 3,5 GHz.
Just a correction, you will loose up to 10% depending on the application. And it also remains to see if the cores in linux will be able to be "parked" allowing for cores being utilized to use higher pstates on the like it can in Windows 8 (which btw should also improve even older Phenom II processors as well).