Yeah, if you want to use LLE ist actually better using a quadcore CPU
A Core i5-2500k from Intel is the best choice

Do you think i can upgrade my CPU my computer p6540d hp pavillion
Yeah, but you need more than a good CPU
* CPU: Intel Core i5-2500k
* MoBO: P67/Z68 (for overclocking)
* 64-Bit OS (faster than 32-Bit)
* 4 GB RAM
Or: Wait till Ivy Bridge. Ivy Bridge 3750k is about 10% faster than the i5-2500k
So i need a new MoBO too, It's so expensive, anyway i will try it first before i buy the hardware LOL.