View Full Version : Intel 6850K core throttling After Voltage Increase.

10-20-2016, 06:33 PM
Greetings Guys.

I Have Increase Core Voltage From 1.25 to 1.30v to get more Stability, but When passing Prime95 test to the system, I have noticed that now the CPU is throttling his Cores.

First, as some of you suggested, we thought it may be Thermal Throttling, but after monitorizing the CPU with CoreTemp, none of the cores passed 71 C so that possibility is very unlikely.

So now I think that due to the power demand increase, something in the OS or the Bios is limiting the power comsumption and force the cores to throttle when the CPU demands more power.

As It's my first Overclock I'm a bit lost here, any clue about what may be causing this throttling?

Many Thanks.

Arne Saknussemm
10-21-2016, 06:37 AM
Do you have active cooling on VRMs?

10-21-2016, 12:07 PM

What are the spec of your rig ?

But a step from 1.25 to 1.3 is a very big step. I dont have any exp in 6 cores.

Am guessing you PSU is sufficient ?

If all is good i would RMA the chip.

10-21-2016, 01:13 PM
I'm Affraid Not, only active cooling is on the RAM Sticks, and, of course, the CPU that has an H115i water Pump.

I have Changed Power Profile In W10 to a custom one with max CPU usage. Then entered the BIOS and set the AVX Offset Multiplier to min I Could that was 1, I mean that I tried to input 0, but the Bios just changed it to 1.

(It was on Auto)

Downloaded Intel XTU and ran Prime95 v289 . Al Cores Stressed properly, but Intel XTU said that the number of Active Cores Was 3. On the other hand, CoreTemp was showing that the 6 cores were Stressed, please check PIC:


Also, sometimes Prime95 says "Unable to Detect some of the Hyperthreaded logical CPUs" And mess with the number of cores my system has. This is begining to give me a Headache, any clues pls Guys?

Many thanks

10-21-2016, 01:21 PM

What are the spec of your rig ?

But a step from 1.25 to 1.3 is a very big step. I dont have any exp in 6 cores.

Am guessing you PSU is sufficient ?

If all is good i would RMA the chip.

Thanks for answering Tommi, forgot to add specs sorry.
Intel 6850K CPU, Mobo is Asus ROG Rampage V Edition 10., 32gb Ram 3200 Cl15, PSU Is seasonic Snow Silent 1050w, so I doubt its a PSU Issue.

Arne Saknussemm
10-21-2016, 02:24 PM
Always a good idea to have a fan blowing on VRM if you are overclocking. Much more necessary than RAM for instance...often overlooked.

However in this case seems something is amiss with CPU....cores missing is strange.

I would try to reflash BIOS if latest...or update BIOS to latest...and then test?

You have 8pin and 4pin ATX power populated?

10-21-2016, 02:34 PM
Yup Arne, Bios is flashed to las version, and The 8 and 4 pin power connectors in the Mobo are populated.

Anyway After looking Again at the CPU-Z pic, It says max TDP is 140W.

I have read that 6850K can eat 200W easily when Overclocled to 4.4Ghz. Do you think that problem may be here? is there any setting in the Bios that limits this power?

Arne Saknussemm
10-21-2016, 04:56 PM
Well, the missing core thing bugs me...

But for classic throttling you either look at temps on the CPU itself or VRM temps.

For "power" try raising CPU current capability in Digi+ section

10-21-2016, 05:10 PM
It may be a false report from the Intel benchmark? Have read that sometimes report false stuff. Is there Any other program I could use to check If all cores are working?

Arne Saknussemm
10-21-2016, 05:20 PM
Windows resource monitor will do that...disable any other program polling sensors and run a stress test....

Get a fan pointed at vrms just for testing....

10-23-2016, 02:37 PM
Akne Just to be sure, and sorry for Newbie Question. VRM section is that one with Capacitor and Mosfets located directly over the CPU socket right? I mean this:


Arne Saknussemm
10-23-2016, 05:09 PM
Yeah, that's the one...there is a heatsink on the back of the board too in that position...if you can get airflow there too it's a good idea....if the standoffs permit a bit of air to get there....

There is a heat pipe off to the large heatsink covering the I/O panel too, of course, this will take some heat away...so generally some airflow across the top part of the board...

Just jury-rig something up to test if this is contributing to the problem...

10-24-2016, 01:02 PM
Ok akne I wont be able to be at home and work In the comp for 2 Days but yesterday I did a test you may find Interesting: (still not with one fan at the VRMs sorry)

First I lowered a litte the CPU volt to 2.850v And set Cache volt to Auto. and Raised the current limit in the Digi+ section to 120% just because if the problems were caused from a current shortage. Also enabled All the monitors on Intel XTU. And ran prime95 v289, results were better but still weird.

At first all seemed to run properly, and I thought I finally hitted the JacKpot with the settings:


At this point all were running properly, XTU still was showing that active cores were only 3, but It was reporting 100% load on all cores? This is weird, is any kind of reporting error? or 3 of my cores are really not working? Coretemp also shows 6 cores working at 100%, I can't understand this guys, any help pls?

Then 10 mins into the test, one of the cores started to drop performance from 100 to 60% with no apparent cause:


Then, 10 more mins into the test and another core lowered it's performance to 60%:


At this point I decided to Stop the test and surrender, lowered the Overclock to 4.3Ghz and run test Again, with no problem this time. This pic is taken with the test runnning for more than a Hour there I had to stop the test:


So I must admit I have no freaking clue on whats going on with my rig. Anyone have any idea pls?

As allways many thanks for your interest, when I got back home will repeat the test with a fan pointing at VRM's

Arne Saknussemm
10-24-2016, 01:52 PM
I never use XTU so I'm not going to be much help there...I think it recently needed an update with new Windows 10 AU...?

Honestly I'd use Realbench for the stress test just to eliminate reporting or load error with XTU.

Maybe try AIDA 64...see if anything else shows thrown cores. Don't know if you have the Intel turbo boost driver installed etc...and what settings?

Raise current cap to max just to eliminate it as a variable etc.

10-24-2016, 05:24 PM
Yup XTU may be outdated with W10, Will Download and Install Realbench when I came back home

I Don't remember Installing Intel Turbo, but maybe the Mobo did it automatically when I installed the CD, How can I check If I have it installed pls?

btw max current in the bios is 240% wont this be too much? bI don't want to fry the CPU

Arne Saknussemm
10-25-2016, 05:27 AM
I don't know how to check if it is installed....maybe download and install latest version...

If my understanding is correct that current cap is like a "power" slider and setting 240 is simply getting it out the way...I do this when I OC and nothing has happened to me...but set less....try 140% etc...the lower settings

10-25-2016, 09:38 AM

you are still using a lot of voltage for the speed you running at.

Did you ever use the auto OC on from the UEFI ? TPU1 and TPU2. TPU1 is for air, guessing AIO unless you have the 240 rads. TPU2 is just custome loop.

Use them and run a test and see what the voltage draw is and what speed it is at. Then go full manual and start dailing in max draw. After that run stress test and drop your volage with 0.010 on very test you do. If you crash up up your voltage with 0.005.

This mostly how i roughly check the pontential of my cpu. I just tell you this because your voltage is bugging me..

But this is me and this how i test.


10-25-2016, 11:07 AM
Thanks for your suggestions tommiboy.

About the voltages. Do you also have a broadwell-e CPU? I say this because the new 6800, 6850, 6900 and 6950K, Uses about 1.35v - 1.4v to get max OC that is around 4.4 - 4.5Ghz in all the reviews I have checcked

New Broadwell-e family are considered to be poor Overclockers, Thats why I think my 4.3Ghz at 1.285v are in the safe zone?

10-26-2016, 12:49 PM
Hi Krorghar,

yes it is a hard cpu to OC and it requires a hole lot of voltage. I realize just now you already tuned down your voltage. Seems you did hit a sweet spot on your cpu.
Compared to other cpu's you are now running below average on voltage :-) At least on the data I fast screened.

Is your problem on the throtteling solved ?

XTU is bugging all over the place. Am only ussing the benchmark utillity. Its pretty heavy and i can compare the score to other scores.

10-27-2016, 11:49 AM
Hi Tommiboy thanks for your Interest.

I won't be able to be at home for a week now. I can't wait to get back home and try all your suggestions. At this point the 4.4Ghz is still giving some problems, 10 mins into prime95 test one of the cores seems to lower its load to 60% with no apparent cause, ten mins more and another core shows the same behavior, I don't know what is causes this, but It seemed really weird and I stopped the test.

Lowered settings to 4.3Ghz and ran the same test with no problem for more than a hour.

So now I have two options, just forguet about it, and take those 4.3Ghz as good, or get back to 4.4Ghz and continue fighting with the system.

Honestly 4.3 Ghz sounds like a defeat, I think that my sample still have much more potential, well see.