Unless the orginal stuff was real junk or put on wrong these new fancy greases are not going to make that much difference. A few degrees at best. Was your system running cooler before and has been getting hotter as time rolls on? If so maybe it's time to look for the real obvious stuff first. Like dust in the case vents in the front and back, Fans that are dirty and slowing down, Dust in the heat sinks and the condition of your cpu fan. Anywhere air was made to flow through. Some of those areas can be really hard to see. Open it up, get a flashlight, take your time, and really look around close.
If your over clocking anything all bets are off