AMD Cool n Quiet not Working - FX-8320

Hello, I'm running a dual boot with Windows 7 and Windows XP, having a little trouble getting Cool n Quiet to work in Windows XP SP3 32bits, the cpu clock always stays at 3.7GHz no matter which power profile I select or whether the pc is at idle or at load.

Cool n Quiet feature is enabled in BIOS and it perfectly works in Windows 7 SP1, so I assume there's some driver or hotfix / patch I'm missing for it under Win XP?

My BIOS is latest version (F2) and Windows XP is fully updated, full PC specs are at my signature, hopefully someone knows what I'm missing to get it work, thanks.