It was in french but here it is in english but just for L2 :
http://www.inklineglobal.com/tips/11_cpu.html
Reboot...
And for L3, you just have to add a new DWORD 32 BITS value at exactly the same regedit place and rename it : thirdLevelDataCache .
In CPU-Z, check the cache level 3 value, here 6 MBytes, so 6 x 1024 = 6144, for the value of "thirdLevelDataCache ".

Reboot...
Apparetly, it gives some extra power to the computer especially for multitask, I can notice it so far ! The cubase cpu monitor is quieter on the same heavy file.
Cheers !