Overclocking 2500k

General Techniq

Jul 21, 2011
I'm looking to overclock a Core i5 2500k to 4.0-4.5 ghz. Preferably, without having to mess with the voltage.
It's a new build, here's how I plan to clock it.......

-Change Bios multiplyer to x40, then Prime for 10 minutes, then raise to x41, then Prime for 10 minutes, etc.. etc.... until I hit 4.5 ghz

-I plan to...
Limit CPUID Maximum
Power Technology
C1E Support
OverSpeed Protection
Spread Spectrum
..then.. Enable:
Internal PLL Overvoltage
Execute Disable Bit
Intel Virtualization Tech

....if I can find all of this in the Bios.

Am I missing anything? Is there something else I should consider?
I've nearly hit my limit for researching and absorbing new [strike]crap[/strike] stuff into my brains for this. I'm looking to make this last leg of this build go as simple and quick as possible. (....background info below)

Background Info: (with a little ranting, feel free to tldr this part)
--I just finished building my first gaming PC. It was more troublesome than I'd anticipated. I'm very lazy when it comes to things like this, and am on the fence about whether or not all this was worth the trouble.
--I've just finished running Prime95 for 3 hours, AFTER installing the OS/Drivers/NetSecurity/Steam(TF2,NuclearDawn).
I ran the blend test with the case side panel off (mostly because I hadn't installed that sidefan yet, due to not having enough 3pin-to-molex or 3pin-Y adapters yet).
Real Temp 3.60 had the max temp at 54 and min temp at 28 (52 and 31 average across 4 cores).
--I had problems installing a Gigabyte Windforce GTX 560 ti, that led to a 2 hour round trip to Microcenter to exchange it for an EVGA GTX 570 HD which installed just fine and is working well so far (ran a little TF2 to test). It isn't OC'd... "yet"
I not only have plans to OC this card, I also plan to add a second one right before BF3 releases (SLI), with both of them OC'd.
--I'm ONLY using Prime95, Real Temp 3.60, and CPU-Z for the purposes of monitoring and load testing my system while I configure it for stability/power.
--System Specs:
-Z68MA-D2H-B3 (I highly discourage power-gaming PC builders from using micro-atx MBs, unless they plan to use water cooling and a third party fan controller thingy. Wish someone had warned me about the obvious space/header issues, since my HS comes close to shorting the GPU if I turn it one way and touches a RAM card when turned the other way, while I only have the one CPU fan header with a single system fan header for a 6 fan case (wtf) but like five freaking usb headers when my case only uses one and like 8 sata connections when I only needed two... -_- I really hope that I can sli from the third PCIe slot to the first one, because the second slot is so close to my first one that the cards will be on top of each other)
-Core i5 2500k (the entire time I was seeking advice for parts, everyone kept telling me to get the 2500k instead of 2600k. Not a single one said, "IF you do NOT plan to sli high-end cards, get the 2500k," but it's cool. You live and learn, and now I'm learning to OC stuff... good times.)
-Hyper 212 Plus (I'm done with direct-touch heat-pipe coolers after my experience with this. Seems that I'd had been better off using water cooling, or a NON-direct-touch pipe cooler)
-CM HAF 912 (The HAF series seem like great cases, really. However, I was REALLY wrong when I said "convenience is overrated". Really really wrong)
-Corsair Vengeance 8gb (2 DIM?) CL9 DDR3-1600 Dual-Channel RAM (why can't these just automatically be recognized by the MB at their listed specs? what is this XMP bios function that I keep hearing about, and why do I have a feeling that I don't want to use it to correct the memory issue? Why do I feel like I paid way too much for this memory kit?)
-Antec HCG 900w (I was wondering why this PSU wasn't more popular, until I got to the wire manage portion of my build. Not looking forward to re-sorting my power connections to accommodate the sli in the near future, either.)
-500GB SataIII Barracuda HDD (is this really the fastest mechanical drive for the price? I kind of feel like I might have let another fry's sales guy dupe me again...)
-DVDR-RW (I'd need to look at the receipt to identify this part any further. I literally told the guy, "give me something cheap," and I have a feeling I'm gonna regret it later. But, that's what the extra drive bays are for, right? At least I can find some use for one of those 6 extra sata headers on the MB.... microATX....)
--All-in-all there's 8 120mm fans in my system (6 on case, 2 on heatsink) that, with the help of the GPU fans, provide for a healthy slightly negative airflow, which I'm told is optimal.

--During this project, I've learned much more about PC hardware than I'd ever known and had ever wanted to learn in my entire life. I know this makes me seem like a "lazy n00b" to some people, but that's just it... as far as PCs go, I am a lazy n00b.
I never wanted to know about - + airflow, cas latency, 12v rail amps, burn/stress/load tests, lapping, ESD, the secret art of nVidia gpu model naming, 80plus certifications, tweak-this-optimize-that, Amazon's horrible packaging practices, BS PC component and service part return policies, headers, cable management, CMOS, etc.. etc.. etc...
-I just wanted to get my PC gaming on :)

--Just like so many like to say, this system building thing is easy enough to do. However, this only applies to a certain group of people. Seriously.
-You guys are in a class all your own. PC building isn't just for "some" people.... it's for a select few. The term "dime a dozen" will NEVER apply to this group.
-I'm still on the fence about whether or not I'm to be part of such a group. My lady's been giving me some deathly looks and off-hand comments the last few days, and my text inbox and voice mail is filled with messages from peeps who think I've been blowing them off. I'm two weeks behind on all my favorite TV series, and two days behind getting my tux to the cleaners in time for a wedding coming up next weekend.
-All this researching and parts hunting and issue resolving has come close to leaving a bad taste in my mouth.

The worst (best?) part???
-After having gone through all this trouble, just to get my PC gaming on, I don't think that I could ever waste another dollar/euro/yen/ruble/whatever towards a retail PC ever again for the rest of my life.
I'm not in the business of being stupid, and there's no way I could purchase a retail PC without finding it to be a stupid waste of hard-earned money after all of this.
-It's like I've taken a bite of an apple from the Tree Of Knowledge. Ignorance was bliss.
I guess I am indeed a part of this PC Gaming/DIY/Enthusiast/etc.. group, now.

Damn you, [strike]Eve[/strike] [strike]PCgaming[/strike] [strike]TomsHardware[/strike] [strike]PC Community[/strike] DESTINY! You did this to me. :)


Apr 1, 2011
That was cute. I'm so lazy I haven't put my side panels on either yet and its been like 20 hours of gaming. My first build recently and I agree too much stuff to learn but its impossible to buy a prebuilt pc.


Dec 28, 2002


It's like I've taken a bite of an apple from the Tree Of Knowledge[/color]. Ignorance was bliss.
I guess I am indeed a part of this PC Gaming/DIY/Enthusiast/etc.. group, now.
Yes it does sort of grow on ya. :sol:

But, to give you some info regarding voltages to the CPU. You might be able to use a 40X without changing voltages, depending on how you overclock.

If you just raise the Turbo Boost that will limit the other cores.

If you want all 4 cores overclocked then I suggest reading this. LINK

I know, more reading, but if you do exactly as explained and heed all warnings, you will indeed achieve your goal of a 4.5GHz OC.(or more if you desire) You will also feel proud of yourself for having done this as well my friend. :D

You have already learned a lot of new information basically because you did not know what you were getting into, like all of us in the beginning of our OC'n.

I'm two weeks behind on all my favorite TV series, and two days behind getting my tux to the cleaners in time for a wedding coming up next weekend.
You think thats bad? Wait til you get that thing where you want it. You won't be able to keep off it. :whistle:

Lastly, there is no subsitute for knowledge of that which you are about to undertake. :sol: You can take that to the bank.

Good luck to you.


Nov 29, 2011
When you have a successful and stable CPU overclocking, the feeling is different, it is priceless my friend because it means you did something extra ordinary that a simple PC user don't know and can't do because they are just PC user. Unlike us who knew the ins and out of the machine that we ourselves built with determination to be different from an ordinary PC user.


Jan 11, 2012
looks like you've put a lot of thought into this... maybe too much.

i've got an EVGA board with my 2500k, so I can use an app within Windows to OC.

literally just slid the bar from x33 to x44. stable at 4.4GHz for weeks now with no problems.

lol. it isn't some elite club. every computer i've ever built was twice as easy as any legos set or model i've ever put together. you buy like 6-7 different parts, slap them together, and connect the cables.

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