The problem with upgrading your CPU is that you would also need to upgrade your motherboard if you wanted to make any meaningful upgrade. Even upgrading to a better CPU that's compatible with your motherboard would be a waste of money, as the upgrade in performance would be meager at best.
You need to upgrade your motherboard if you want to make a big CPU upgrade.
On a different note, have you really overclocked your pentium to 6GHz?! That's impressive.
Anyway, I hope that helps answer your question!
DonQuixoteMC