Overclocking Sandy Bridge 3930k on an Asus board questions

[Midphase]

I am running an i7 3930k on an Asus Sabertooth X79 board with the latest OS X 10.8.2 installed and I have a few questions.

First of all, if I understand correctly, Turbo and SpeedStep modes don't work on 2011 boards/CPU's right? So should I be disabling Speedstep and Turbo in the BIOS since they are not being used?

Secondly, my method of overclocking is, once I disable the Speestep/Turbo modes in BIOS is to set my BLCK (base clock frequency) to 131% which yields about a 4.17ghz over clock. While I'm at it, I also set the VCore voltage to 1.350 to keep the Automatic from going above that.

Am I doing this wrong? Should I be using the Multiplier instead? What's the difference?

My system is running stable right now with no KP or weird behavior. Temperatures are in the upper 40's and low 50's under load. For some reason, if I go even a hair above 4.2ghz in my BLCK setting, my computer won't boot, and setting it right at 4.2ghz seems to give me some weird issues with Aftereffects and Handbrake.

If anyone has any info or advice I would highly appreciate it. Anyone with a similar build who could give me some better idea on what to adjust in my BIOS would be awesome.

Thanks!

 

[Ewoodster]

I am running an i7 3930k on an Asus Sabertooth X79 board with the latest OS X 10.8.2 installed and I have a few questions.

First of all, if I understand correctly, Turbo and SpeedStep modes don't work on 2011 boards/CPU's right? So should I be disabling Speedstep and Turbo in the BIOS since they are not being used?

Secondly, my method of overclocking is, once I disable the Speestep/Turbo modes in BIOS is to set my BLCK (base clock frequency) to 131% which yields about a 4.17ghz over clock. While I'm at it, I also set the VCore voltage to 1.350 to keep the Automatic from going above that.

Am I doing this wrong? Should I be using the Multiplier instead? What's the difference?

My system is running stable right now with no KP or weird behavior. Temperatures are in the upper 40's and low 50's under load. For some reason, if I go even a hair above 4.2ghz in my BLCK setting, my computer won't boot, and setting it right at 4.2ghz seems to give me some weird issues with Aftereffects and Handbrake.

If anyone has any info or advice I would highly appreciate it. Anyone with a similar build who could give me some better idea on what to adjust in my BIOS would be awesome.

Thanks!

Hi midphase,

the easiest way to overclock your CPU is by raising the multiplier. This only affects the CPU clock speed. You've raised the base clock which also affects QPI and RAM speed. So you're overclocking the bus which connects the CPU and the Northbridge and your memory as well. I recon your RAM is the limiting factor and may cause instabilities in high load scenarios.

 

[Midphase]

Thank you Ewoodster, I'll try sticking to the Multiplier method and see what happens.

But for the record, disabling Speed Step and Turbo is a good idea on these CPU's?

 

[Midphase]

I wanted to follow up on this since someone else might find this info useful...and there really isn't a whole lot about this topic that I have been able to find.

First of all, apparently I confused Speed Step not working with Turbo not working. Apparently the two are quite different and Turbo does work on Sandy Bridge CPU's in OS X.

I went back to the drawing board and restarted my entire overclocking process, I had been frustrated that the fastest reliable OC that I was able to obtain was 4.17ghz by setting the BCLK at 134% and not running as a multiplier (I had also disabled both Turbo and Speed Step in BIOS). Reading from other people's posts, it would seem that at the very least a 4.5ghz OC should be quite attainable using this CPU...so I gave it another try.

I re-enabled Turbo (but still disabled Speed Step), I used a multiplier of 47 and tweaked the BCLK frequency just a hair higher than normal at 103% (3.3ghz instead of the standard 3.2ghz). This gave me an effective OC of 4.8ghz while in Turbo mode, and a base CPU frequency as displayed in OS X of 3.91ghz (weird, I know).

While I was at it, I also enabled my BIOS to use X.M.P. for my RAM (which upped its clock to 1600-something mhz) and I upped the Vcore voltage to 1.370 (a hair high, but still within safe guidelines).

This gave me a Geekbench 32 score of 20,850...now we're talking! My temperatures were in the 48º during idle and up to around 70º during peak usage. I'm also factoring in that it's still very hot outside and that my thermal paste is still breaking in. Hopefully when it cools off a bit it will bring those temps down a few degrees.

One last thing, although most apps seem to work fine at the 47 multiplier (48 causes KP's), Handbrake would lock up about halfway through an encode. I use Handbrake as a stress test and I was concerned in the computer acting wonky during peak usage, so I went back into the BIOS and scaled the multiplier down one notch to 46 and the Vcore voltage down to 1.360 to help with the temperatures. So far this last tweak seems to have gotten Handbrake to behave, the temperature change during peak usage was negligible, and the Geekbench score went down a hair to 20,480. Weirdly enough, changing the multiplier from 47 to 46 or even 45 seems to have no effect on the CPU speed as recognized by the OS X About This Mac which keeps saying that the CPU is running at 3.91ghz...oh well, as long as it all works I'm not too worried about that.

I'll run more tests and verify stability some more tomorrow...but so far it looks promising and I finally feel like I'm getting the performance that I was hoping to get from my machine.

P.S.

I decided not to use a liquid cooled CPU heat sink. Too many nightmare stories of leakage ruining stuff. I have a decent fan cooled sink that is probably ok. I think if if went to a liquid cooled one I could probably lose a few degrees of heat, and possibly push the multiplier up another couple of notches...but I don't feel it's worth the risk.

 

[mckinsey123]

I know this is a slightly old thread, but I would really appreciate some help.

I'm running a 3930K on an ASUS P9X79 Pro motherboard, and no matter what settings I choose, I cannot get my overclock to be registered in OS X. I can achieve a stable overclock of 4.4GHz in Windows 7 (havne't tried OC'ing any higher yet) but whenever I boot into OS X my overclock is ignored and the CPU runs at stock 3.2GHz.

My settings:

OC set to 'manual'
BCLK 100
Turbo multiplier 44
Speedstep disabled, turbo enabled (have also tried with turbo disabled)
CPU Vcore at 1.3v (stable in Windows 7 at good temps).

I'd be so grateful if someone could point out where I'm going wrong. What's particularly frustrating is that when I use the 'OC Tuner' option in the AI Tweaker (basically an auto overclock), I do get a boost in OS X. The Tuner sets the BCLK to 126.37 and the ratio to 33, but the fact that my speed is then 4.04GHz suggests that OS X is only factoring in the BCLK, not the multiplier (4040MHz divided by 32, the stock multiplier, = 32, so it looks like the multiplier being used is always stock. If the 33 multiplier was being used with the BCLK of 126.37, the CPU would be at 4.17GHz, which is what I'm seeing in Windows).

Thanks in advance for any advice.

 

[monty007]

Don't know if you have seen this thread:

{great success} - Mikhail's Video Editing Hack Pro - 3930k/ GTX670/ SabertoothX79/ H100i/ 3x Vertex4 SSD/ 16GB Ram

he has a guide with pictures for your board and cpu. He has done an excellent job with the overclock - stable at 4.8 GHz with operating temps under 44 degrees Celsius.

Monty

 

[morg]

Hi Midphase,

Wondering if there have been any significant changes/updates since you wrote this?

I also have a 3930k with an h100i cooler now, Sabertooth x79 and looking to overclock but running into the same problems...

Any tips/links much appreciated!

 

[stirfry2112]

mckinsey123 or anyone else find a solution? I am having the same issue as mckinsey123 - multipliers no longer take effect in MacOS, but BCLK do. No idea why the sudden refusal to Overclock, all my old saved profiles no longer work! The only thing that does work is using the OC Tuner, but that just uses the BCLK. Tried updating my BIOS to the latest 4801 and still no solution. Anyone have a suggestion?

Thanks!

Asus P9X79 Pro & 3930K running 10.9.5

 

[stirfry2112]

I think it might require proper installation of the VoodooTSCSync Kext (which I have not used in some time), going to try re-installing it when I get a chance but would love it if someone could chime in with some proper knowledge.

 

[stirfry2112]

Scratch that, just installed VoodooTSC 6-core from MultiBeast 7 and no change at all. Still no reasons why the multiplier no longer works. I also tried updating OS to 10.10 from 10.9, no change. So strange. Any help would be great.