Hey guys - I've been having a strange problem working with the clock on my new rig using a 2500k. I'm running it on mostly standard settings in the bios, and am perfectly stable up to a 43x multiplier, including under extensive prime95 and IBT runs.
The problem comes when I go any further beyond 43x. At 44x and above, the multiplier that CPU-Z reads from my Core 0 bounces around, usually staying in the 40-42 range. This is under either prime95 stress testing or IBT. Obviously costs me a few hundred mhz, but more importantly, I'm not getting the chance to see if I can go higher.
While the system's stable at up to 4.5ghz (the highest I've touched), it won't maintain those speeds for any significant length of time. Heat doesn't seem to be a problem. Using a 43x max multiplier I've yet to see a peak temp at or above 60C, and using a 45x max, I've never seen it touch 63C.
I'm using a fixed vcore of 1.28V right now - and actually wasn't sure whether it would be better to use offsets or absolute values.
Is this a case of me needing to up the voltage, mess with Vdroop, or is there some other setting I may have missed? I'm relatively new to the whole OC thing, so that's 100% a possibility. Or have I just gotten unlucky with a CPU with a lower wall?
My system, for reference:
2500k currently stable at 4.3ghz
Cooler Master 212+ CPU Cooler
ASRock P67 Extreme4 motherboard
MSI Frozr II HD 6950
8GB G.Skill Sniper RAM (9-9-9-24 @ 1600mhz)
OCZ Vertex 2 SSD is the system drive
When your overclock reduces itself by a couple of multipliers under load like that, it means either:
1. Your Turbo Boost Power Limit is too low.
2. Your Core Current Limit is too low.
Try setting Turbo Boost Power Limit to Manual, then setting Short Duration Power Limit to 300, Long Duration Power Limit to 250, and Long Duration Maintained to 56. Reboot then try Prime95 and/or IBT. If that doesn't fix it, set Core Current Limit to 300 (while leaving the other settings at the new numbers).