Maximum PC

Hey everyone. I'm working on getting a 4.5ghz overclock on my Core i5-2500k. So far, things are going pretty well, but I'm not understanding something that I'm seeing in CPU-Z. Right now I am running my CPU at 100 BCLK * 45 to acheive 4.500ghz. When I load up CPU-Z, I see 4500 MHz for Core Speed, x 45.0 for Multiplier, and 100.0 MHz for Bus Speed. Vcore is set to 1.315v in BIOS. CPU-Z shows 1.304v. These values are all while the system is idle.

The problem occurs when I kick off a stress testing program such as Prime95 and the CPU goes under full load. I'm noticing that the multiplier will drop (it may scale anywhere between x40 to x45, at random it seems). I have speedstep and turbo mode turned off, all power states (c1e, c3, and c6 turned off), and thermal protection turned off. I can't think of what would be causing the multiplier to drop like it is.

My temps are right around 58c - 60c full load, using an h80 cooler. I just set the cooler tonight, so I'm still waiting for the Arctic Silver to seal. The rest of my build is:

ASROCK Z68 Extreme4 Gen3
Core i5-2500k
Corsair H80 cooler
8GB DDR 1866 RAM, using XMP profile for speed / timings

Any suggestions?

Thanks in advance!

Have you tried Throttlestop?

http://www.techinferno.com/2011/04/05/i ... own-build/

Do you get errors under p95? (Like rounding?)

I am going to guess not.

Check this link: http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-Intel-core-i5-2500k/1