Overclocking my i5 2500k thread. Success?

David_VI

David_VI

David_VI

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Hey its me.. again

New build built and working (I believe). Now to get it OC'ed as thats what was intended and everyone was praising the 2500k for being easy to OC.

So only ever OC'ing my ole Q6700 and badly, the new bios of the Gigabyte P67a-UD4 was confusing so I followed the Bit-tech guide.

I ignored a few things like changing PCH SATA Control Mode to ACHI, as it would only boot via my external esata drive and ignore my internals with that on, so changed it back to IDE.

Anyway upon following the guide and being confused by coretemp not showing the change (Apparently it doesn't yet show the OC but only stock on these Sandybridges) I noticed Windows was showing it, as was CPU-Z.

So ran Linx and heres the result.
Does it look okay? Temps and speed?
How far can I go and any tips from other users of the i5 2500k? and/or similiar Mobo?




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Cheers!
 
Dea924 said:
good few hours.. depends how long you leave your pc running, some people do it for 24hours just to be on the keen "it definately is stable" side
Click to expand...

Must have been at least an hour, but there was the BSOD.
CPU core was at 1.3v Is that what should rise or is Vcore different to CPU core? Learning as I go here! :)

Temps all seem fine though.
 
David_VI said:
Must have been at least an hour, but there was the BSOD.
CPU core was at 1.3v Is that what should rise or is Vcore different to CPU core? Learning as I go here! :)

Temps all seem fine though.
Click to expand...

VCore/CPU voltage are the same thing.

Here's an overclocking guide which will give you an idea of what else needs tweaking:

http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/4

Despite what it says don't change the base clock from 100.
 
Surveyor said:
VCore/CPU voltage are the same thing.

Here's an overclocking guide which will give you an idea of what else needs tweaking:

http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/4

Despite what it says don't change the base clock from 100.
Click to expand...

Cheers Surveyor, your userid has been a familiar site in my newb like threads, I thank you for your help!

That is the guide I followed to get this clock so I may have changed the base clock to 1005, so move it back to 1000 I will
And somehow I need to figure out where the noise is coming from, think it might be the Kuhler rad + fans, something to do once i've settled on an OC and got everything else working well, need as much quietness as possible.

Anyway, I upped the voltage by a notch or 3 and seems the PC is still alive as its still showing up in the network :)(I'm on laptop elseware)

Thanks
David
 
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As above, if the BSOD error is #124, you need more vcore or vtt. Unfortunately I can't tell you exactly what this should be because every board/chip is different however try adjusting your vtt to 1.16 and up your vcore to 1.32 I assume you have set your PLL to auto? If you're still not stable try upping you vcore allot to say 1.38 and then play with your vtt. Unlike other platforms, sandy seems to be very sensitive to vtt changes and there is a so called 'sweetspot', atleast with the 2600K. For example, with my overclock if I adjust my vtt to 1.18/1.2 Prime Blend will crash within minutes however at 1.16 it's stable for hours. The good news is that if you havn't got it right Prime seems to fail very quickly.

Once you have your PC stable, I would highly recommend that you use an offset voltage (it's an option within the vcore setting in your voltages menu). The UD4's (atleast with the 2600K) suffer from horrible vdroop (a loss of voltage when your chip is put under load) which will mean that you need to put a higher voltage in the bios to achieve stability when under load in windows. The offset voltage essentially adds more volts - on the fly, when your PC is under load. It's also a nice power saving feature meaning that we your chip rolls back to 1600Mhz using speedstep, your voltage also rolls back.
 
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David_VI said:
That is the guide I followed to get this clock so I may have changed the base clock to 1005, so move it back to 1000 I will
Click to expand...

The reason why the guide prompts you to adjust the base clock is that if you want say 4600Mhz, simply entering 46 * 1000 (the UD4 measures the PCI bus at a higher level of precision than some other boards) in the UD4 (it would actually be 1000), you will not get 4600Mhz because the PCI frquency drops in windows. So I actually have mine set to 1007 at present to give me 100.5 in bios and 4823.3 Mhz.
 
I left Prime95 running after increasing the voltage to 1.32v (fixed in edit), didn't change the baseclock yet as I was already letting Prime run while I was posting here earlier.

Anyhow I just awoke and saw no BSOD, however one of the workers in Prime95 says this and was after 2hours
FATAL ERROR: Rounding was 0.5, expected less than 0.4
Click to expand...

The other workers were still running, 8 hours.

Does this mean its unstable or something else?
Anyway I will recheck my bios, fix the baseclock and the other settings beh* has reccomended, IF I can figure it out :o
 
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beh* said:
The reason why the guide prompts you to adjust the base clock is that if you want say 4600Mhz, simply entering 46 * 1000 (the UD4 measures the PCI bus at a higher level of precision than some other boards) in the UD4 (it would actually be 1000), you will not get 4600Mhz because the PCI frquency drops in windows. So I actually have mine set to 1007 at present to give me 100.5 in bios and 4823.3 Mhz.
Click to expand...

Ah.

I thought there was an extra nought in there and the base clock was being overclocked to 105MHz.

On the MSI P67A-GD65 it's a similar thing.

If you set the base clock to 10,000 it ends up at 99.something MHz.

I turned off spread sectrum and that leaves it at exactly 100.
 
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Heres the temps and prime from overnight.
Is it normal for there to be such a difference in temps for each core?

coretempl.jpg

prime95fatalerror.jpg


I've changed the VTT to what beh* reccomended and the vcore to 1.308v (At least thats what CPU-Z says)
Running again :)

David
 
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Looks good David. I get the same difference in temps at idle so not to worry. Keep pushing your overclock as high as you feel comfortable (in terms of vcore). You will reach a point when at a certain multiplier your chip will require more than 1.38vcore (the max recommended rating). It shouldn't take to long to find this point. Once you have it you can start experimenting with higher/lower PLL and VTT. BTW, You only want to be doing 8 hour prime runs once you are 30+ mins stable at a certain vcore. The idea is that you incrementally bump up your multiplier and vcore until you reach a point in which you overclock requires either a raise in voltage that your not willing to accept or an exponential raise in vcore which will only result in a minimal gain in performance. The latter is what some overclockers call the 'sweet-spot'.
 
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Thanks beh*! Great info and very useful. Will have to try to apply it! Can I just re-clarify something? My base clock settings turn out to be fine right? Or should it be back at 1000?

Anyway, I said I was running Prime95 with the changes suggested. I got no errors this time and ran it for 4hours.

The error on worker 4 previously occured after 2 hours so this should mean i'm okay for now? Can do some more tweaking also.

Here it is..
What do you think?



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Can't see the end of Worker 3, forgot to scroll but thats 0 errors.

David
 
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I upped it from 45x to 46x and got BSOD after a while of prime65, I upped the core volts by one or two notches and still got issue, so have gone back to 45x and testing that for now..

Should I have to increase the voltage much for just 46x? What am I to expect and did I miss something. The baseclock is back at 1006 instead of 1000

David
 
Hi David, As long as the PCI frequency is as close to 100 in windows then that's fine. Unfortunately the voltage required for each mutiplier jump is not linear. What vcore are you at?
 
I'll get back to you on that, i've gone back to the settings from the bit tech guide to check something and i've noticed the noise from my case is the antec fan on the kuhler. It was proper quiet when I first built the system a day ago. I've now removed the fan and put just my Xilence fan with the radiator and its near silent except from a buzzing noise if you're close..

Any idea why the antec fan suddenly became loud? I plugged it into a sys fan to see if it really was the antec and it is, awfuly loud.

:\
David
 
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