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Considering that the P8P67 PRO is the most popular choice for a SB mobo, I was wondering what other people managed to get OCing with the 2500k. I wanted to compare stable OCs and see if I can manage to get something higher.

I use a Cooler Master 212 as my CPU Cooler.

Currently I'm at 4.5GHz (100BLCK * 45 multi)
Internal PLL Overvoltage - Enabled
Load-Line Calibration - High
Phase Control - Extreme
Everything else AUTO

I'm wondering if I should change my Voltage to manual (CPU-Z gives a max reading of 1.368V under load with the current auto setting) but the main reason I stopped changing things was because 1) it's quite stable as is right now and 2) I'm getting ~80C using Prime95 and I don't want it to get any hotter.

What's getting me confused is that I've read other people manage a 4.5GHz OC with much less voltage and generate much less heat using Prime95 under similar conditions (ie. no crazy expensive water cooling solutions). Am I missing something in my BIOS settings?

I'm running an MSI P67A-GD65 (B3) but i'm at 4.635Ghz (45x103) with my voltage at manual 1.35V. With max temps at 70-75. According to CoreTemp. I'm running the CM 212+ with Arctic Cooling MX-4 as my Thermal paste. I'm using my old Xigmatek HDT-1283 fan instead of the Stock Coolermaster 212+ fan for acoustic reasons. If it's available on your motherboard, manually set your voltage to 1.35 and manually set your CPUIO voltage to 1.005 and see if that can lower your temps while still keeping you stable.

I'm pretty sure you have more headroom than that. I had to clock all the way up to 4.8 @ 1.4V to get max temps above 80.

Turiel wrote:

What's getting me confused is that I've read other people manage a 4.5GHz OC with much less voltage and generate much less heat using Prime95 under similar conditions (ie. no crazy expensive water cooling solutions). Am I missing something in my BIOS settings?

Could be luck of the draw, some chips are just better than others.

Hmm. I spent the last 4-5 hours trying different settings in the bios but here's what I figured out:

4.5GHz requires about ~1.7V max. Everything on Auto except 100*45 and 1.35V will result in one of my cores getting a hardware error. CPU-Z also shows 1.7V while Prime95 is running when the CPU Voltage is set to Auto in BIOS. I haven't tried manually setting my CPU Voltage to 1.7V yet but unless it'll drop my temperature significantly I don't see why I should prefer it over just Auto, which gives me a higher chance at stability.

I don't think I can shave off any degrees in max temperature (mine peaks at about 79C) because of my CPU cooler. Maybe the fan is in the wrong direction (I placed it with the blades facing the same direction as the rear fan in the Corsair 600T. Is 80C safe for the i5-2500k for 24/7 operation? (I know daily usage will never be like running Prime95 but I just want to make sure).