Cpu overclocking by multiplier problem in bios

[no_one]

Hy;
I have an Asus M4a78-vm motherboard and an Athlon 5000+ x2 Black Edition;
The default multiplier for my cpu is 13, but i want to overclock the cpu by raising the multiplier to 15.5 (3100Mhz) and the cpu voltage by +50mv;
Everithing is ok, but when it boot's up windows, when i go on properties by right clicking the "my computer", there it seems that my cpu runs at 3100Mhz and the overclock gone right, but when I take a look on Cpu-z and Everest, there is another "story" and my cpu looks like it's running on its default frequency at 2600Mhz;
What is wrong ? the overclock from bios goes ok, but at the startup programs in windows, probably i have a program running that modify my multiplier to the default value ?
If I use the AMD Overdrive , I can easily overclock it to 3100Mhz, by raising the voltage and the multiplier;
If anyone has an idea, please give me suggestions
10x

 

[jitpublisher]

Did you disable cool and quiet in the BIOS?

 

[no_one]

no, i didn't;
this could be the problem ? I will try to disable it and I will reply with a message within 10min

 

[no_one]

Did you disable cool and quiet in the BIOS?

SOLVED; thanks a lot man, you solved my problem, it works now