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Trying to find a stable overclock for my 2500k

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May 28, 2012 2:37:22 PM

Hi guys,

This is my first time overclocking my system. I followed one guide, but testing it I saw it was very unstable, so I followed a video guide instead (See edit).

1.) I originally kept crashing in Prime 95, but followed a video guide and now it appears more stable. Even if my system didn't crash from Prime 95 (like if I just restarted it), it turns on and off about 3 times, and finally flashes the Mobo screen and goes to Windows on the 4th. Every now and again, an American Megatrends screen will come up telling me that my overclock failed. Once I hit a stable overclock, will my system boot up like normal on the first try?

2.) The guide tells me that I SHOULD be stable at 1.35 V, and yet after maybe 10-20 minutes on Prime 95 my system will crash. What should I do about this? Just keep increasing the voltage? Are the crashes damaging my computer?


Thanks for the help guys! I just want to hit 4.5 without worrying if it's stable or not.


Edit: 20 minutes on Prime 95 and no crash so far, here's a screenshot:


EDIT 2: So I followed his guide:
http://www.youtube.com/watch?v=WMZoWOpry40

This is what I changed:

-Base clock frequency from 101 to 100.
-LLC from High (50%) to Extreme (100%)
-Phase Control and Duty Control from Auto to Extreme
-VCCIO voltage from Auto to 1.1 (on auto it was like 1.056)
-CPU PLL voltage from Auto to 1.9 (on auto it was like 1.729)
-Under the monitor tab, I disabled CPU Q-Fan control, so my CPU fan runs at max speed in order to keep my CPU the coolest. I don't care about the noise, because I can't even hear it over my two 6950's at 50% fan speed.

The only things I couldn't follow, were things that weren't options. For instance, there was no options for a VCSSA voltage on mine, and on the video he didn't have options for DRAM Ref voltage.

Specifically, what do you think about changing the LLC, Phase Control and Duty Control, and the VCCIO and CPU PLL voltages? No idea what these do, but I followed the guide so I hope he knew what he was doing! I actually know enough about LLC, so will setting that to extreme hurt my CPU more than the overclock itself?


Sorry for the wall of text guys, but I'd greatly appreciate the help!
May 28, 2012 10:48:27 PM

"-Base clock frequency from 101 to 100. " <--why, it does nothing but harm your stability with a sandy-bridge processor. They do not take kindly to modifying the BCLK speed, keep it at 100, and only use Multi's. 1.344 Vcore is very high for a 2500k, most people get stable at 4.5ghz between 1.300-1.325 Vcore.
May 28, 2012 10:55:43 PM

----------------------------
IntelBurnTest v2.53
Created by AgentGOD
----------------------------

Processor: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz
Clock Speed: 3.30 GHz
Active Physical Cores: 4
Total System Memory: 8168 MB

Stress Level: Maximum (7144 MB)
Testing started on 5/28/2012 4:56:04 PM
Time (s) Speed (GFlops) Result
[16:59:08] 151.589 119.2417 2.949493e-002
[17:02:12] 151.107 119.6220 2.949493e-002
[17:05:15] 151.762 119.1053 2.949493e-002
[17:08:16] 150.272 120.2869 2.949493e-002
[17:11:17] 149.812 120.6561 2.949493e-002
Testing ended on 5/28/2012 5:11:17 PM
Test Result: Success.
----------------------------
I don't know why it says it's at 3.3Ghz, because CPUID reads 4.5, maybe it's talking about stock, but I know it's overclocked.

Anyway, it survived the burn test, would you say it's stable then? Temps hit on average mid-high 80's, 89C max, but I know the point of this test is to really crank up the heat. And I don't nearly get as much doing other things. I idle in the 40's.

Edit: I changed back VCCIO and CPU PLL back to auto. I kept LLC, Phase Control, and Duty Control to extreme though. I'm trying to figure out if I should revert the last to to auto or LLC to a lesser setting.

Either way, it survived Intel Burn Test without crashing (at 1.35V), so I know something is right.
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May 28, 2012 10:56:50 PM

Fireraga said:
"-Base clock frequency from 101 to 100. " <--why, it does nothing but harm your stability with a sandy-bridge processor. They do not take kindly to modifying the BCLK speed, keep it at 100, and only use Multi's. 1.344 Vcore is very high for a 2500k, most people get stable at 4.5ghz between 1.300-1.325 Vcore.



That is weird. It was 101 originally. But it's stock speed was 3300 mhz. I reduced it to 100 so I got exactly 4.5Ghz. And what are saying 1.34V is high? In most guides all over the internet, the recommended voltage for 4.5 is 1.35? It bounces from 1.344-1.36, because it is staying around 1.35 (which is what I entered as my manual voltage.
a c 283 à CPUs
a c 110 K Overclocking
May 28, 2012 11:04:49 PM

apav said:
That is weird. It was 101 originally. But it's stock speed was 3300 mhz. I reduced it to 100 so I got exactly 4.5Ghz. And what are saying 1.34V is high? In most guides all over the internet, the recommended voltage for 4.5 is 1.35? It bounces from 1.344-1.36, because it is staying around 1.35 (which is what I entered as my manual voltage.


He's saying that 1.35V shouldn't be needed for 4.5. 1.32V-1.33V should be all that you need unless you're just very unlucky, and you might be able to go lower than that.
May 28, 2012 11:07:26 PM

DJDeCiBeL said:
He's saying that 1.35V shouldn't be needed for 4.5. 1.32V-1.33V should be all that you need unless you're just very unlucky.



I guess I am :(  The moment I go 1.345 or below Linx crashes right away and Prime 95 crashes after several minutes (of course both not at the same time).
a c 283 à CPUs
a c 110 K Overclocking
May 28, 2012 11:10:03 PM

Ah, that sucks. I've only seen a few that need 1.35V for 4.5. I can do 4.6 at 1.35V, but it's just the luck of the draw with CPU's, unfortuately.
May 28, 2012 11:19:32 PM

DJDeCiBeL said:
Ah, that sucks. I've only seen a few that need 1.35V for 4.5. I can do 4.6 at 1.35V, but it's just the luck of the draw with CPU's, unfortuately.


Well it's no big deal to me. .5V less is only a drop in a few Celsius, and I don't get nearly as hot in games as I do in those two programs.
a c 283 à CPUs
a c 110 K Overclocking
May 28, 2012 11:21:17 PM

Yeah, no real world use will ever push it as hard as Prime and IBT.
May 29, 2012 12:22:23 AM

48 minutes of Linx so far with these settings and it hasn't crashed so far... how long do I need to stress test it for?
a c 283 à CPUs
a c 110 K Overclocking
May 29, 2012 12:28:23 AM

Supposedly a few hours (2 or more), but if it hasn't crashed yet, it probably won't.
May 29, 2012 1:59:13 AM

DJDeCiBeL said:
Supposedly a few hours (2 or more), but if it hasn't crashed yet, it probably won't.



So after 2 hours of Linx, no crashes! I guess I'll also try lowering the voltage by a little. But I really think setting LLC to extreme is what's making me stable. Because I'm getting more than 1.35, which is what I set the manual voltage to.

What do you think I should do with LLC and Phase Control/Duty Control? I'm debating if I should put LLC back to high and change the Phase Control and Duty control back to auto. If I do all that, and if it doesn't crash, should I keep it that way?
a c 283 à CPUs
a c 110 K Overclocking
May 29, 2012 2:13:56 AM

That gets slightly out of my realm of knowledge, honestly because I don't even mess with Phase and Duty control, personally, and have never seen the need to (just left on auto).

And with my board, LLC is either On/Off/Auto. No levels, so I can't really help you much there either. I leave it off completely because it gives the CPU WAY more voltage than it needs for some reason (guessing "On" is Maximum on boards that give you the choice of levels).

In fact, all I do to OC to 4.5 with my board is set the main multi to 45 and put the offset at +.020 (can't use a manual Vcore with this board). That's literally ALL I do. As you can tell, this board is pretty terrible for OC'ing, but it gets the job done.
!