Overclocking 2500k on Gigabyte Z68XP-UD3P

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requiem99

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Just a thread to post questions and results about this motherboard/cpu combination. I've had a few issues getting stable @ either 4.4 or 4.5 using settings suggested at various forums and guides around the web (though the settings discussed in this post have yielded 30~ min of PrimeFFT stability and counting), so I figured I would find some people here who've already got it done and dusted.

Currently used this guide as a baseline (I know it's not a P67 but they share a lot of similar settings, and I'm not an overclocking noob so common sense + googling carries me through most of it):

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

Currently testing stability @ 4.5ghz, with settings (as specified in bios, but incorrectly reported in windows with both cpuz and hardwaremonitor):

1.315 vcore
Load-Line level 6
QPI/VTT 1.12
System Agent Voltage 1.135
BCLK freq 1003

Picture follows... (keep in mind the incorrectly reported vcore, and possibly more, as i certainly did not set 1.5 OR 1.128 vcore):

bGwgk.jpg


Another question: because I have a BCLK drop of 2 (i.e. 1003 = 100.3mhz but drops to 100.1mhz after I boot) should I drop it one more to 1002 to hit exactly 100mhz or does it need to be "over" 100 to ensure stability? I can't find an answer to this one on google. Also, is there variation in BCLK during high load as with vdroop?

I'll update this post as I accumulate more information and test results. My stability testing consists of 1 hour Prime95 smallFFT followed by a few loops of 3dmark CPU section, followed by various recent games.

So far I've not passed the Prime95 part of it, but I'm getting closer... 45 min now as I finish writing this post.

edit1: Ok Prime95 passed an hour test. On to game testing. Another question: Anyone know if I should keep all those chip features disabled in bios as suggested at bit-tech? EIST, C1E, CPU Thermal Monitor, etc.
 
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Btw, just ran Coretemp and it says 1.3861 under load which matches the 2nd entry in HWMonitor (under Gigabyte DES).
 
Dammit, it was stable for 4 hours of Alpha Protocol and Deus Ex, but as soon as I played League of Legends I had a hard lockup within 5 minutes. Backed off to 4ghz with the same current settings and will update later today... I really don't want to upvolt it any more since the actual voltage under load is now 1.39 -- I guess I just got a bad 2500k that can't do 4.5 at reasonable voltage. :(
 
I don't understand why the ram would be an issue when I'm not overclocking the ram at all. There's nothing in that post (which I had already read before you posted it) referring to it.
 
As I can't seem to stabilize 4.5ghz or even 4.4 with reasonable voltages I'm going to try for flat 4ghz with as little voltage as possible. Will post results tomorrow morning.
 
Stable all night @ 4ghz running 1.25v in bios (reported 1.27 in windows, 1.22 under max load). I'll be dropping it inch by inch to find out what the minimum stable voltage is for 4ghz.
 
we don't have the same board but we have similar setups so i'll give you my 2 cents. on my gigabyte board adjusting the voltage and playing with LLC was a mixed bag. in the end i settled on leaving my voltage on auto, bumping the 2600k multi to 45 and calling it a day. it's been rock solid at 4.5ghz on auto.

also, my 2500k on my asrock p67 pro3 was the same way.

the bios you use on your GB board is important because i had a rock solid 4.8ghz OC on f6, and f8 went and screwed it all up. none of the manual settings worked the same after i updated my bios. the way LLC worked was all different too.
 
novadaemon said:
we don't have the same board but we have similar setups so i'll give you my 2 cents. on my gigabyte board adjusting the voltage and playing with LLC was a mixed bag. in the end i settled on leaving my voltage on auto, bumping the 2600k multi to 45 and calling it a day. it's been rock solid at 4.5ghz on auto.

also, my 2500k on my asrock p67 pro3 was the same way.

the bios you use on your GB board is important because i had a rock solid 4.8ghz OC on f6, and f8 went and screwed it all up. none of the manual settings worked the same after i updated my bios. the way LLC worked was all different too.
Click to expand...

I'll keep all of this in mind in the future when I want to eke a bit more life out of this cpu. For now, undervolting @ 4ghz is pretty bitchin. With the NH-D14 the temps aren't much above room ambient, and although I haven't tested performance yet, I would expect the resolution I run at (1080p) followed by the GTX480 are the bottlenecks now, not the CPU. Since this rig will be used almost exclusively for gaming and gaming related tasks (capturing game videos, encoding game videos) I don't feel pushing the CPU much further is necessary at this point. I do appreciate the information. Thanks. :)
 
oh, i also wanted to mention that I got higher OC's running at 8gb vs 16gb. it's a very subtle thing, but even though all my ram was stable in memtest, popping out 2 sticks to lower the stress on the IMC allowed for higher clocks, but i'm not going to give up having 16gb of vengeance for a couple hundred extra mhz. for the sake of oc'ing you should try to get stable on 8gb first.
 
I'm not that extreme. I prefer a lesser OC at very cool temps. 4ghz is still bitchin' for me, I'm totally satisfied and will be gaming all winter on this.
 
For closure I ended up undervolting to 1.23 in bios (1.26 reported idle and 1.21 reported under load in windows) @ 4ghz rock stable 48 hours and all stress testing is done, the cores max out in the high 50s under load, and I've been playing plenty of games without any issues. Very happy with the result.
 
As a minor update for more information I've since run the above attained 4ghz OC on this board/cpu nonstop 24/7 since the last post.

I've had to up the voltage every 6 months or so by 1 step to maintain stability (silicon aging or other complex engineering, I guess?), but no other changes.
 
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