CPU cores vary in temp and OC question

[legolasthearcher]

Hello all,

A couple of questions from a newb that despite a few searches I could not find answered. I apologize if these questions are common and I just missed them.

Preface:
I recently built a new computer. This system is as follows:
CPU: Intel i5 2500k
MB: MSI P67A-G45
RAM: G.Skill 6GB (3 x 2GB) PC 1600 (PC3 12800) F3-12800CL9T-6GBNQ
VC: ATI Radeon HD 6950 2GB
Case: Antec 300

Q1)
Yesterday my new cooler came in to replace the stock cooler. I have purchased the Cooler Master Hyper N520 and I installed it using the Arctic cooler directions for thermal paste application, with a thin vertical line of thermal paste after having cleaned both the CPU and the Heatsink with 91% Alcohol.

After installing it, I ran OC genie II (MSI's auto overclocker) and after rebooting, it settled on a 4.2 Ghz clock.
I then ran RealTemp and Prime95 to check the temps both at idle and full load.
During testing, I noticed that there was an ~4-5 degree difference (Celsius) between Core 0 and core 1 (with core 0 being cooler), Core 1 and 2 were about the same, and there was an ~3-4 degree difference between Core 2 and 3 (with core 3 being warmer).
Basically it looked something like this:
Proc. Idle Load
CPU0: 28C 59C
CPU1: 32C 63C
CPU2: 31C 63C
CPU3: 35C 66C

Is this normal/ok? Or is this indicative of an incorrectly installed CPU cooler?

Q2)
After OCII overclocked the system, for some reason it raised the DRAMM Voltage to 1.65v, but seemed to keep my memory at 1333 rather than raising it to 1600. It is my understanding (after reading all the great threads about OCing Sandy Bridge) that you want to keep the DRAMM Voltage below 1.65v, (despite what they seem to say here: http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/5 ) and so I manually lowered it to 1.55v. Is this ok? And if not what should I set it at?

And finally can I run my memory at 1600 (since it is rated at that speed) at 1.55v rather than 1.65v? I checked Newegg's listing of the ram and it says that its voltage ratings are 1.5-1.65v. Does that mean it runs at 1.5v when underclocked and 1.65v at 1600, or does that mean that it is safe to run it at 1600 and 1.5v?

Thank you for the help, and if I left anything out let me know and I will try my best to answer.

 

[snoopy7548]

Hello all,

A couple of questions from a newb that despite a few searches I could not find answered. I apologize if these questions are common and I just missed them.

Preface:
I recently built a new computer. This system is as follows:
CPU: Intel i5 2500k
MB: MSI P67A-G45
RAM: G.Skill 6GB (3 x 2GB) PC 1600 (PC3 12800) F3-12800CL9T-6GBNQ
VC: ATI Radeon HD 6950 2GB
Case: Antec 300

Q1)
Yesterday my new cooler came in to replace the stock cooler. I have purchased the Cooler Master Hyper N520 and I installed it using the Arctic cooler directions for thermal paste application, with a thin vertical line of thermal paste after having cleaned both the CPU and the Heatsink with 91% Alcohol.

After installing it, I ran OC genie II (MSI's auto overclocker) and after rebooting, it settled on a 4.2 Ghz clock.
I then ran RealTemp and Prime95 to check the temps both at idle and full load.
During testing, I noticed that there was an ~4-5 degree difference (Celsius) between Core 0 and core 1 (with core 0 being cooler), Core 1 and 2 were about the same, and there was an ~3-4 degree difference between Core 2 and 3 (with core 3 being warmer).
Basically it looked something like this:
Proc. Idle Load
CPU0: 28C 59C
CPU1: 32C 63C
CPU2: 31C 63C
CPU3: 35C 66C

Is this normal/ok? Or is this indicative of an incorrectly installed CPU cooler?

Q2)
After OCII overclocked the system, for some reason it raised the DRAMM Voltage to 1.65v, but seemed to keep my memory at 1333 rather than raising it to 1600. It is my understanding (after reading all the great threads about OCing Sandy Bridge) that you want to keep the DRAMM Voltage below 1.65v, (despite what they seem to say here: http://www.bit-tech.net/hardware/cpus/2011/01/07/how-to-overclock-the-intel-core-i5-2500k/5 ) and so I manually lowered it to 1.55v. Is this ok? And if not what should I set it at?

And finally can I run my memory at 1600 (since it is rated at that speed) at 1.55v rather than 1.65v? I checked Newegg's listing of the ram and it says that its voltage ratings are 1.5-1.65v. Does that mean it runs at 1.5v when underclocked and 1.65v at 1600, or does that mean that it is safe to run it at 1600 and 1.5v?

Thank you for the help, and if I left anything out let me know and I will try my best to answer.

It's normal for the cores to have different temperatures (think of their physical locations) but your temps do seem a little high, although I haven't read much about your heatsink. What's your Vcore and room temp?

As for the thermal paste application, a dot in the middle (size of 1-2 BBs) is usually the preferred method (unless I'm behind the times here) for non-HDC coolers. I have the Hyper 212+ and I obviously had to do a different method (vertical lines) but the results were great. If it's any help, I'm running my i5-2500K at 4.2GHz @ 1.21Vcore and my idle temps are around 29C +/-2C with my load temps being around 51C +/- 2C. I'm going to push it to 4.5GHz this weekend and see how low I can get on the Vcore/temp.

I'd also be wary of using the auto-overclocker since it applies more voltage than necessary. You'd be better off doing a little research and tinkering around with it yourself. I had mine running at 4GHz a few days ago but I used the auto-voltage setting and I was getting pretty much the same temperatures I am now. I actually used the same guide you linked to as a starting point for myself and managed to get a pretty decent and very stable overclock with my P8P67.

What RAM do you have? As long as you're running it in-spec you should be fine. You could try running it at 1600 @ 1.5V and run some memory tests to see if it's stable. If so, keep it there.

 

[legolasthearcher]

Thanks for the info Snoopy. I used the vertical line method for the thermal paste as that is what the Arctic Cooler guide said to use for our chips and what a few other members here recommended.

As far as the OCing goes, I am beginning to realize that I should probably just follow that guide I linked and then lower the RAM voltage and see if I can be stable as you said. It seems that no one likes the auto overclocking.

Thanks again, I will post results here when I am done.

EDIT: I forgot that my ambient temps are about 28-30~ degrees C as we just had a heatwave.

 

[legolasthearcher]

Ok, so I have now OCed my computer manually, and here are the two pics of my system running under Prim95 (the second pic shows CPU-Zs Memory info:

My one remaining question right now is, why does MSI's Control Center show my ram as 1333 when I have it set in bios as 1600 and when CPU-Z seems to show it running at 1600?

Thanks again for all the help

 

[pantsaregood]

No idea, but I'd ignore the utility's readings and trust CPUZ. On top of that, be sure you're overclocking from your BIOS and not that utility. Software overclocking should be avoided whenever possible. Your CPU also may be capable of more than 4.2GHz. I advise trying it.

 

[Morg.]

Like he said, try closing in on 5ghz

besides, I think that when you overvolt your CPU, you can also overvolt your RAM.

And you don't run your CPU at stock, why do it with your RAM ? ^^

MSI control center might be reading the thingy on the RAM that says "I'm a 1333mhz x-y-z-n latency chip @ 1.5v" instead of the current Bios config.

As always, software OC and OC utilities should be avoided.

 

[betasub]

MSI control center might be reading the thingy on the RAM that says "I'm a 1333mhz x-y-z-n latency chip @ 1.5v"

SPD?

 

[Morg.]

SPD?

Thank god somebody remembered -- not me though.

 

[degibson]

Is this normal/ok? Or is this indicative of an incorrectly installed CPU cooler?

Measuring per-core temperature is hard. Sensor calibration can vary.

 

[legolasthearcher]

Thanks so much for the answers and advice.

So first off, yes I am overclocking in the Bios not with that utility. (and if all it does is just read the info on the chips, then I think I will just uninstall it and use CPU-Z, GPU-Z and RealTemp.

I briefly tried going to 4.5, and 4.4 last night, but at 4.5 it wouldn't boot into windows, and at 4.4 it booted but then bluescreened after about 15-20 ish. min. of solid Prime95.

I was going to try again today or on Saturday, as last night all I did was just up the clock speed without messing with the voltages beyond what you see listed.

Does it look like my numbers are ok on the CPU? anything I need to change?

Thanks again for all the help and input

 

[tweakboy]

its not full contact is it would be with a lapped CPU , and nice thermal ..

your 70c will be 60 or less c.

 

[legolasthearcher]

Hey Tweak,

I am afraid I don't understand the question. I don't know what you mean by "full contact" and "lapped CPU".

If by full contact you mean the Heatsink on my cooler is fully touching the CPU, then to the best of my knowledge it is. But if it means something else, then please clarify.

Also I am not sure what you mean by "your 70c will be 60 or less c." since right now my CPU is running around the low 60s at full load.

Thanks

 

[Diogenes2]

its not full contact is it would be with a lapped CPU , and nice thermal ..

your 70c will be 60 or less c.

Nonsense....

 

[betasub]

I am afraid I don't understand the question. I don't know what you mean by "full contact" and "lapped CPU".

...

Also I am not sure what you mean by "your 70c will be 60 or less c." since right now my CPU is running around the low 60s at full load.

Don't worry, nor does Tweak. Diogenes2 said it in a single word

 

[legolasthearcher]

LOL, thanks for the clarification guys

 

[legolasthearcher]

Ok, so it has been a very busy few weeks, but I finally got around to trying to overclock my CPU a little more, and I am running into problems and need some help.

So, first a recap of my system:

CPU: Intel i5 2500k
MB: MSI P67A-C45
HeatSink: Cooler Master Hyper N520
RAM: G.Skill 6GB (3 x 2GB) PC 1600 (PC3 12800) F3-12800CL9T-6GBNQ
Video Card: ATI Radeon HD 6950 2GB
Case: Antec 300 (all 4 case fans installed)
PSU: ANTEC 650W EA650 RT

My problem is that I can't seem to get a stable clock above 4.3ghz. My current Bios overclock settings are here:

And as far as I can tell, these are the only settings I can change to overclock the CPU.
I was able to get to 4.5 and run both Prime95 (ran for about ~10 min.), and Intel Burn Test (at Very High Memory Settings) no problem, but if I just let the system run for a while it will eventually bluescreen.

The CPU Core Voltage was set at 1.3 for the 4.5 OC, but since CPU-Z was showing 1.344 Volts used under load, and since I saw that post from the Intel guy here saying that Intel recommends not going above 1.35v, I don't see how I can reach a stable 4.5 OC.

Am I missing something? or do I just have a weak i5 and need to live with it.

Thanks for the help, and let me know if I need to supply anymore info.

 

[Lightflash]

Intel released a paper with a 1.52V max voltage, so your voltage is okay. Only thing I would say is slowly increase the voltage until the 4.5OC is stable.

Otherwise your settings look like everything I have read on MSI overclocking.

 

[tweakboy]

Hey Tweak,

I am afraid I don't understand the question. I don't know what you mean by "full contact" and "lapped CPU".

If by full contact you mean the Heatsink on my cooler is fully touching the CPU, then to the best of my knowledge it is. But if it means something else, then please clarify.

Also I am not sure what you mean by "your 70c will be 60 or less c." since right now my CPU is running around the low 60s at full load.

Thanks

That is normal that is how it should be. Enjoy your nice rig. thx gg and gb

I got a nice 8c difference between my 0 and 1 then next 2 are 8c lower.
This is why they make thermal paste and its important because it trys its way to fix the gaps,, not touching in full form evenly. No bodies is the same.. some may claim but no,,,

You did good with the installation of the custom HSF :thumbsup:

 

[legolasthearcher]

Intel released a paper with a 1.52V max voltage, so your voltage is okay. Only thing I would say is slowly increase the voltage until the 4.5OC is stable.

Otherwise your settings look like everything I have read on MSI overclocking.

Ok, so the processor can take up to 1.52V without adverse effect? Where did the 1.35V-1.38V number come from?
Thank you for the info, I will do some searches and see if I can find more on the voltage maxes cause there is quite a difference between those numbers.

But everything else looks ok? That is good to hear. Thanks again.

 

[Diogenes2]

You shouldn't have to go anywhere near 1.52 to get 4.5 .. 1.35 or so is more realistic ..

 

[Hogan773]

I'm scared to go above 1.3 let alone 1.52!

I've been running a mild 42x OC for past few months at 1.22 using offset voltage.

Tonight trying a 45x with a negative offset that is giving me 1.26 under load. Passed Intel Burn Test. I'll start Prime in a few mins. My experience with some of these lower-voltage attempts is that Prime crashes ASAFP even if I can surf normally and pass Intel BT all at the same time prior to trying Prime.

Its a game of trial and error.

 

[legolasthearcher]

I'm scared to go above 1.3 let alone 1.52!

I've been running a mild 42x OC for past few months at 1.22 using offset voltage.

Tonight trying a 45x with a negative offset that is giving me 1.26 under load. Passed Intel Burn Test. I'll start Prime in a few mins. My experience with some of these lower-voltage attempts is that Prime crashes ASAFP even if I can surf normally and pass Intel BT all at the same time prior to trying Prime.

Its a game of trial and error.

How does "offset voltage" work? I was looking in my Bios, but I don't see anything called that.

 

[tweakboy]

OMG 1.5 will get you to 6000Mhz ,, lets brake a record someone with Sandy.. thx

 

[Lightflash]

Just to clear up what I meant. I was saying 1.52V is the max that Intel said the processor would be able to handle without causing problems.

As for the 4.5OC, I meant increase voltage from base voltage, not 1.52V.

Sorry if that caused any confusion on my part.

 

[Hogan773]

I'm scared to go above 1.3 let alone 1.52!

I've been running a mild 42x OC for past few months at 1.22 using offset voltage.

Tonight trying a 45x with a negative offset that is giving me 1.26 under load. Passed Intel Burn Test. I'll start Prime in a few mins. My experience with some of these lower-voltage attempts is that Prime crashes ASAFP even if I can surf normally and pass Intel BT all at the same time prior to trying Prime.

Its a game of trial and error.

Prime crashed within 2 minutes! Yet I passed Intel Burn Test 5 runs at Max.

I don't get it, since most people act like IBT is much more "harsh" on the CPU than Prime and therefore ferrets out instability much more quickly. In my case, it seems Prime will often crash within a couple minutes if my voltage is out of whack too low, but IBT might make it.