Overclocking test findings on an i7 4930k

[simonm]

So i decided to watercool my i7 4930k 3.4GHZ using a Corsair h100i GTX for the purpose of overclocking my CPU..... still trying to get my head around it all and i have had a few blue screens which means i need to tweak things still.... latest overclock seems stable so far but i need to run it for 24 hours without it crashing....

 

Anyway, for those interested in the results (feel free to weigh in).

So to test the speed, firstly my stock cinebench score was as follows:

 

Stock 3.4ghz - 795

O/C - 4.4 GHZ - 1130

O/C - 4.5GHZ - 1157

 

Tests during a render scene (render scene was a current project of an exterior scene with a lot of vegetation and multiple dwellings) - 3.4 million polys. Vray ender engine 3.20.03 and 3DS Max 2016 with medium settings and a resolution of 1000x666.

 

Stock 3.4ghz - 4m 21 seconds

O/C - 4.4 GHZ - 3m 36 seconds (17% quicker than stock)

O/C - 4.5GHZ - 3m 26 seconds (21% quicker than stock and only 5% quicker than 4.4GHZ O/C).

 

So it looks like i can cut my render times down by 1/5th.

 

My OC settings were as follows:

BLK Frequency 100

Core Ratio either 44 (for 4.4ghz) and 45 (for 4.5ghz)

CPU Core Voltage - 1.45

Enhance Intel Speedtrap technology - Disabled

 

CPU Temps under load dont exceed 62 degrees celcius.

 

Would be interested to see your O/C results and what you have done to achieve that?

[numerobis]

CPU Core Voltage - 1.45

 

Ups... is this using auto-overclocking? I would not go higher than 1.35v for the VCORE. And interesting would be your VCSSA (or SA) and VTT, especially VCSSA, because these are the critical voltages that can quickly degrade or damage you CPU... both should be kept below 1.15-1.2v to be safe.

What is your LLC? It is possible that Auto sets it to "high"... i would keep it in the middle for 24/7.

I don't know how you are testing stability and temperatures, but if it is using cinebench, then it is the wrong tool. Cinebench is not really heavy load, it needs lower voltages and you can easily get 15°-20°C higher temps in other, heavier tasks. So Cinebench-stable does not mean much.

 

And why no Speedstep? It should be possible to get it stable with power saving features (incl. dynamic voltages). I always use offset and not fixed voltages.

Edited August 19, 2015 by numerobis

[simonm]

some of the language you just said it very foreign to me lol - im a newbie overclocker so some of those words dont mean much to me.... yet.....

I literally followed this tutorial 100% - am i doing something wrong? I also use prime 95 and i plan on doing a longer test.

 

 

 

Ups... is this using auto-overclocking? I would not go higher than 1.35v for the VCORE. And interesting would be your VCSSA (or SA) and VTT, especially VCSSA, because these are the critical voltages that can quickly degrade or damage you CPU... both should be kept below 1.15-1.2v to be safe.

What is your LLC? It is possible that Auto sets it to "high"... i would keep it in the middle for 24/7.

I don't know how you are testing stability and temperatures, but if it is using cinebench, then it is the wrong tool. Cinebench is not really heavy load, it needs lower voltages and you can easily get 15°-20°C higher temps in other, heavier tasks. So Cinebench-stable does not mean much.

 

And why no Speedstep? It should be possible to get it stable with power saving features (incl. dymanic voltages). I always use offset and not fixed voltages.

[numerobis]

As i said above, you should check your voltages. A vcore of 1.45v is too high in my opinion. Max safe value according to intel is 1.4v. Maybe with a good custom water loop this is ok. But personally i would keep it below 1.35-1.375v

And concerning VCCSA and VTT... there have been long discussions in some forums after some 3930K had died and the conclusion was that going higher than 1.2v on these voltages is very critical (it is the same for the 4930K)

https://rog.asus.com/forum/showthread.php?19926-3930K-C2-Degradation

[Nikolaos M]

I agree with numerobis in everything. I have the 3930K and it has almost the same oc behaviour with the 4930K.

 

For a 4.4GHz oc you will need either a manual voltage of around 1.28-1.30V, or a negative offset of about 0.05-0.04 (values vary depending on the chip).

 

LLC at a "regular" level (25%) would be good for a modest oc.

PLL overvoltage can be disabled if the case is a modest oc.

VCCSA and VTT would be fine at about 1.1V. ANd yes, I've seen too the instructions concerning the 1.2V safe limit.

 

My highest safe oc in terms of voltage levels was 4.8GHz with 1.35V (if I recall correctly). I've once tried a 5.0GHz for benchmark purposes and I got stable at about 1.5V. Of course, the whole thing ended right there. One CB score and back to safety.

[simonm]

thanks for the response guys... you have officially scared me lol...

 

the thing is, all the vids i saw on youtube, showed me basically the same way i mentioned above.

Is there any guide/tutorial you can point me towards? I dont want to make any more assumptions moving forward on this. I have to be sure im doing the right thing as the last thing i need is a malfunction... makes me wonder if 20% speed incrase is worth it.....:\

 

thanks for the assistance guys

[Nikolaos M]

Could you mention your motherboards type? It would be easier to help if we knew that detail. For a 4.4GHz oc you'll need to follow some easy steps. Every motherboard has a defferent BIOS, so someone could give you a simple guide if he knew how the BIOS is organized.

[simonm]

Thanks mate i have the sabertooth x79

 

Could you mention your motherboards type? It would be easier to help if we knew that detail. For a 4.4GHz oc you'll need to follow some easy steps. Every motherboard has a defferent BIOS, so someone could give you a simple guide if he knew how the BIOS is organized.

[Nikolaos M]

Fine piece of hardware, you've got there.

 

OK. Try out these settings. Go to the AI tweaker and set:

1. XMP at the Overclock Tuner

2. By all cores: Give a 44 for starters

3. CPU Core Voltage: Either a manual voltage of 1.28-1.3V or a negative (-) offset of 0.05-0.04V (this is a trial and error thing)

4. Check if the DRAM voltage is correct. Your RAM's xmp profile requires a specific amount of V.

5. PLL: disable that for now

6. VTT and VCCSA: put those at about 1.1V and you're good for now.

 

Next, go to the Digi+Power control and choose a medium LLC. That will cut down some °C and you'll probably wont have stability issues.

 

You can leave the rest settings at Auto for now. Try the above, and give us some feedback. You can check for stability by running a stress test. Run a Prime95 (blend) for a 1/2 an hour and see if something is wrong. I wouldn't advise you to run long and torturous stress tests like Intel Burn test, or Prime95 Large FFTs. They are not realistic and they suck the life out of your cpu for no reason.

[numerobis]

thanks for the response guys... you have officially scared me lol...

Is there any guide/tutorial you can point me towards?

No need to be scared. You just have to keep the voltages and temps within the safe range and everything will be fine.

Some basic guides:

http://forums.overclockers.co.uk/showthread.php?t=18476907 (it's the same for Ivy Bridge-E)

http://www.overclock.net/t/1189242/sandy-bridge-e-overclocking-guide-walk-through-explanations-and-support-for-all-x79-overclockers

http://rog.asus.com/forum/showthread.php?44467-Overclocking-Tips-Beginner-and-Advanced-Guide-to-Overclocking&country=&status=

https://rog.asus.com/forum/showthread.php?38018-Ivy-Bridge-E-Easy-Overclocking-Guide-%96-The-Listy-Wordy-Edition

 

max voltages: http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/4th-gen-core-i7-lga2011-datasheet-vol-1.pdf (page 64)

 

I would try to keep VCCSA and VTT under 1.15-1.2v, better 1.1v. My 3930Ks are running with a VCCSA of 0.975v. High VCCSA is normally only needed if you are overclocking your memory controller (IMC).

And I would not use Prime95 v28.x because it uses AVX2 and FM3 and runs VERY hot, torturing the CPU too much. It's better to use Prime95 v27.9.

Recently i tried Intels XTU for quick tests (which is also using Prime95), but i'm not sure if it really gives good results. I have to test it a bit longer...

[simonm]

Guys thanks so much for your valued responses.... I was away on a ski trip for a few days and only got back....

Will review and try what you guys suggest and report back!!!

 

Hugely appreciate the time and effor youve spent in helping me on this.... legends

[simonm]

hey Nikolaos

 

How do I work this out exactly?

" Check if the DRAM voltage is correct. Your RAM's xmp profile requires a specific amount of V."

 

Fine piece of hardware, you've got there.

 

OK. Try out these settings. Go to the AI tweaker and set:

1. XMP at the Overclock Tuner

2. By all cores: Give a 44 for starters

3. CPU Core Voltage: Either a manual voltage of 1.28-1.3V or a negative (-) offset of 0.05-0.04V (this is a trial and error thing)

4. Check if the DRAM voltage is correct. Your RAM's xmp profile requires a specific amount of V.

5. PLL: disable that for now

6. VTT and VCCSA: put those at about 1.1V and you're good for now.

 

Next, go to the Digi+Power control and choose a medium LLC. That will cut down some °C and you'll probably wont have stability issues.

 

You can leave the rest settings at Auto for now. Try the above, and give us some feedback. You can check for stability by running a stress test. Run a Prime95 (blend) for a 1/2 an hour and see if something is wrong. I wouldn't advise you to run long and torturous stress tests like Intel Burn test, or Prime95 Large FFTs. They are not realistic and they suck the life out of your cpu for no reason.

[Nikolaos M]

Hey Simon!

 

Download cpu-z from here http://www.cpuid.com/softwares/cpu-z.html

 

and tap on the SPD tab. You'll see there all the Jedek and xmp profiles of your memory along with the required voltages. Be sure to check if the xmp voltage is the same as the dram voltage inside the AI Tweaker menu and you are done.

[simonm]

Thanks Nikolaos

 

Ive attached some screenshots. In regards to the voltage, there are 2 readings 1.5 and 1.6... which one do i follow?

 

Also, with the additional RAM i purchased recently (originally had 32 gig kingston beast and now bought another additional 16 gig kingston beast), i noticed that the frequencies are different on them? I was under the impression they were the same... does this matter?

 

 

Hey Simon!

 

Download cpu-z from here http://www.cpuid.com/softwares/cpu-z.html

 

and tap on the SPD tab. You'll see there all the Jedek and xmp profiles of your memory along with the required voltages. Be sure to check if the xmp voltage is the same as the dram voltage inside the AI Tweaker menu and you are done.

[Nikolaos M]

You have two xmp profiles, one @1600 and 1.5v and one @2133mhz and 1.6v. Choose one of them and pick the voltage accordingly.

[simonm]

thanks mate.... 2 things i couldnt find.... they were:

5. PLL: disable that for now

6. VTT and VCCSA: put those at about 1.1V and you're good for now.

 

Couldnt find PLL and VTT/VCCSA? any ideas boss?

 

You have two xmp profiles, one @1600 and 1.5v and one @2133mhz and 1.6v. Choose one of them and pick the voltage accordingly.

[Nikolaos M]

PLL voltage is just after the DRAM adjustment.

VCCSA is just after the VCORE settings.

You'll find VTT as VTTCPU in you BIOS.

 

All these are in the manual (download pdf from here http://www.manualslib.com/manual/415077/Asus-Sabertooth-X79.html?page=78#manual) pp. 3-13 up to 3-16.

[simonm]

Thanks Nikolaos

 

I have done it. However the only thing I couldnt do was disable the PLL voltage as the only options were AUTO or a voltage number... there was no disable option. So i left it at AUTO.

 

Question - if this doesnt blue screen, what do you think I can overclock to? Currently its 44.

 

Attached are the screenshots of the OC.

 

Ill run prime 95 and see how I go. Thanks again and ill post more updates as they come.

 

PLL voltage is just after the DRAM adjustment.

VCCSA is just after the VCORE settings.

You'll find VTT as VTTCPU in you BIOS.

 

All these are in the manual (download pdf from here http://www.manualslib.com/manual/415077/Asus-Sabertooth-X79.html?page=78#manual) pp. 3-13 up to 3-16.

[numerobis]

The PLL voltage setting determines the voltage fed to the CPU's phase locked loop section. The phase locked loop section generates the clock signals for different parts of the CPU that are clocked at different frequencies. You can't disable it. Standard value is 1.8v if i remember correctly. Lowering the PLL can help to reduce the heat and maybe even increase stability.

So what was your VCCSA and VTT setting with the auto overclock?

And what are they now? You can try to lower VCCSA to 0.9-0.95v or even more.

 

VDIMM normally shouldn't exceed 1.5v, maybe 1.55v, but 1.6v would be to much for me. I would try to run the RAM at 1866MHz with 1.5v. But i don't know if this works because there is no XMP profile for this speed. (More than 1866MHz will give you close to nothing but it will stress the memory controller more)

Edited August 20, 2015 by numerobis

[simonm]

Thanks mate

 

I can confirm that i bluescreened on the settings Nikolaos mentioned above during a test render (will now try the offset voltage as i had the CPU volate at 1.29. I will also try what you suggest and report back

 

The PLL voltage setting determines the voltage fed to the CPU's phase locked loop section. The phase locked loop section generates the clock signals for different parts of the CPU that are clocked at different frequencies. You can't disable it. Standard value is 1.8v if i remember correctly. Lowering the PLL can help to reduce the heat and maybe even increase stability.

So what was your VCCSA and VTT setting with the auto overclock?

And what are they now? You can try to lower VCCSA to 0.9-0.95v or even more.

 

VDIMM normally shouldn't exceed 1.5v, maybe 1.55v, but 1.6v would be to much for me. I would try to run the RAM at 1866MHz with 1.5v. But i don't know if this works because there is no XMP profile for this speed. (More than 1833MHz will give you close to nothing but it will stress the memory controller more)

[Nikolaos M]

Pll can be disabled. Just write "disabled " where it says "auto". I have the rampage IV extreme and I have it off. It's mostly needed for high oc, like 4.6 or more.

[numerobis]

i think what you mean is "PLL overvoltage"

[Nikolaos M]

I guess you are right...

Edited August 20, 2015 by nikolaosm