Overclocking a core i5 2500k sandy bridge

Dslocum

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Dec 3, 2011
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Ok ive been doing alot of research about overclocking, it seems really complicated. i was told that "All you have to do is go into bios and change the multiplier from 33 to 45(multiples of 100mhz) disable intel turbo boost and intel speed step and bam you have a 4.5ghz i5-2500k!," then someone else said "You're not going to hit 4.5 at stock voltage, not even on a golden chip, but finding the right voltage for your chip and board is a quick process, even for a beginner." so im curious how do i know what voltage to go with or what to do. All i want is the 4.5ghz overclock, nothing more or less. my system specs are:

Case - http://www.newegg.com/Product/Product.aspx?Item=N82E16811129021
Mobo - http://www.newegg.com/Product/Product.aspx?Item=N82E16813131770
or http://www.newegg.com/Product/Product.aspx?Item=N82E16813157271
Video Card - http://www.newegg.com/Product/Product.aspx?Item=N82E16814127608
CPU - http://www.newegg.com/Product/Product.aspx?Item=N82E16819115072
CPU fan - http://www.newegg.com/Product/Product.aspx?Item=N82E16835103065
Thermal compound - http://www.newegg.com/Product/Product.aspx?Item=N82E16835100007
Memory - http://www.newegg.com/Product/Product.aspx?Item=N82E16820231314
PSU - http://www.newegg.com/Product/Product.aspx?Item=N82E16817371016
HDD - http://www.newegg.com/Product/Product.aspx?Item=N82E16822136830
 
No harm in just setting it on 4.5. If it BSODs, it BSODs, and then you turn it down to 4.4 and then, if that doesn't work, 4.3. You'll be able to hit that. Test it with Prime95 each time for half an hour or so.
Nice links.
 

ebalong

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Sep 11, 2011
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If you don't mind setting it on "autopilot", just flip the TPU switch to "ON", and, in your BIOS EZ Mode, click on "Defaults" (lower right of the EZ mode screen), and "Load Optimized Defaults" (I think this is what it says). That is all I did, and I am not sure if it is the TPU switch enabled alone which does it, or the loading of the optimized defaults, but I seem to be running in automatic, enhanced Turbo mode. Running Core Temp shows my CPU is at ~0.96v and ~1.648 GHZ most of the time, with an occasional spike to ~1.36v and ~4.38 GHZ. I ran Prime95 for 30 min, and the frequency stayed at 4.38 GHZ for the whole time, with temps steady at 55-60C. I have the P8Z68-V Pro, but yours has the TPU switch also, I believe. Unless someone else knows otherwise, it seems like letting the firmware automatically raise your turbo boost is safe, i.e., it wouldn't let your CPU over-voltage or something. So, this is what I run with, it's easy, you just set it and forget it. Of course, if your goal is to reach 4.5 and higher, then disregard.
 

PurpleHayes

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Just to get to 4.0 GHz, you could probably just go into the BIOS and change your multiplier from 33 to 40. Overclocking a Sandy Bridge chip is quite easy; without going into too much detail, here's the basic procedure:

1) Go into the BIOS and increase the multiplier by 1 (33x ->34x), then restart the computer and log in to Windows. Run Prime95 for a bit, and keep an eye on your computer temperatures (there are several applications for this). If Prime95 fails, the OC is unstable and you'll need to revert to your original multiplier. Also, the temperatures shouldn't exceed 60-65 C if you want your chip to last.
-For the initial step you don't need to go up by 1; all SB chips can go up by 100 MHz. Try starting off with something like a 4 or 5 multiplier increase.

2) Repeat this process until you've A) Reached your target speed or B) Prime95 fails. Once that happens you have two options: Go back to the last stable multiplier, or increase your core voltage. WARNING: Increasing core voltage will drastically increase your temperatures, so keep an eye on core temperatures. Move the core voltage up by increments of 0.025 or 0.05 (e.g. 1.25->1.3 V).

A few more pointers:

-You do not want to push core voltage over 1.4 V if you want the chip to last a few years. More than 1.4 V will severely shorten your CPU's life, and it will cause uncomfortably high temperatures.

-Most i5-2500k chips can get to 4.0 GHz just by increasing the multiplier; the tricky part usually comes in when going from ~4.3 GHz to higher speeds. There are some more advanced methods to achieve the really high clock speeds (>4.5 GHz), such as setting Load Line Calibration etc.

-You'll get better clock speeds with a better cooler. Temperature is extremely important; the lower your temperatures are, generally the higher you'll be able to OC the chip.

Lastly, don't be afraid of a BSOD! It's not necessarily harmful to the computer; motherboards today automatically shut down the computer once a BSOD occurs, before any damage can happen. The more research you do, the more comfortable you'll be with overclocking and the better results you'll achieve.
 

Dslocum

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I've been reading alot about it and i was gunna try for 4.5ghz but ill be happy with 4.0ghz, if i just change my multiplier from 33 to 40, do i have to turn off turbo or any other settings? or JUST change the multiplier and dont do anything else?