i7 6700k unstable temperatures

Jun Ho · Apr 19, 2016

Hey guys, recently I've installed a i7 6700k, and I've noticed that it's temperatures while gaming are very unstable.
On games like BF Hardline it goes like: 65c 75c 72c 65c 58c 65c 68c 75c etc etc
The pattern is pretty wild.
I had a i5 4690k before this one, and never saw something like this.
Is it a normal behavior or the temp sensor is defected by any chance
I'm using Artic MX-4 as thermal paste, and used the pea method.
Using the memory ram at 3200MHz.
Thanks in advance!

10tacle · Apr 19, 2016

Several degrees variation between the four cores is normal depending on the application being used. However, generally, when you get up to a 10C variation regularly under load it generally means you have missed screwing down a corner of the CPU cooler and aren't getting optimal contact somewhere.

Are you using the stock Intel cooler? If so, that thing can give trouble in mounting uniformity on the CPU.

Poozle · Apr 19, 2016

What cooler do you have? some watercoolers come "unbound" and do not properly attach to MB causing weird temps.

Jun Ho · Apr 19, 2016

10tacle :

I'm using Enermax ETS-T40F. And I'm pretty sure I've mounted it tightly.
I always check if the hardware components are well put in their slots.
Thanks for your quick reply.

Jun Ho · Apr 19, 2016

Poozle :

I am using Enermax ETS-T40F sir.
Thanks for your reply.
I made sure it was well attached to the motherboard when I installed it.
But if I don't find any other explanation to this, I will try to tighten up the screws even more.

10tacle · Apr 19, 2016

Jun Ho :

Take it off and check your thermal paste disbursement for uniformity. If it looks fine, reseat the cooler and double check you are equally tightening all sides. I've had this issue several times even when I "thought" I had done a good job at seating the CPU cooler. Just remember that a few degrees C variation is normal, but under load a 10C is not and something is wrong (if all four cores are used on the load application).

If you still have the issue again, then there's a chance it's a defect from the CPU cooler contact plate where it meets the CPU may have a flaw that you might not even be able to see with the naked eye.

Jun Ho · Apr 19, 2016

10tacle :

While idling on desktop it remains at around 30c - 32c, without any peaks.
Do you still think that it might be a CPU contact plate problem?
I`ll check the thermal paste later on though.

Gnuffi · Apr 19, 2016

Jun Ho :

my 6700k OC @ 4600 on 1.312v is idling between 20-25 in a 0 active fan case, with only the cpu cooler running

your cpu sounds hot compared to mine, considering i have fans turned off

10tacle · Apr 19, 2016

Gnuffi :

Everyone's ambient room temps are different as are their case cooling airflow solutions. There's a reason why CPU cooler websites like FrostyTech use a temp-over-ambient rating in their cooler reviews vs. raw temperature comparisons.

For example, right now I'm on my i5 4690K with a Noctua NH-D14 air cooler typing this in between gaming and the lowest idle temps in HWMonitor are 29C, 29C, 28C, 30C. My room temp is 25C. Max load temps (running stock CPU, not overclocked) are at 50/50/52/53. This is with a high air-flowing Antec Nine Hundred case.

Dugimodo · Apr 19, 2016

I'd try a stress test on the CPU and see what temps it gets to, something like prime95.
If it gets hotter than you expect or are comfortable with check the heatsink as previously suggested.

Incidentally for those who asked about stock cooling, the 6700K does not come with a cooler. On mine I recycled an old Hyper 212 Evo I had available and my temps are fine, sits around 70 under a stress test with the fan still silent and never gets anywhere near that hot in normal usage/gaming.

I wouldn't worry about fluctuations too much as long as it never exceeds the safe range and the 4 cores are reasonably consistant.
Check Hashers response in this thread http://www.tomshardware.com/answers/id-2771035/6700k-temperatures.html

10tacle · Apr 19, 2016

Dugimodo :

+1 ....Oh yeah I had forgotten with Skylake Intel finally ditched the stock coolers with the K chips (I have three of them laying around from my K builds...what a waste). Thanks for the reminder.

Jun Ho · Apr 20, 2016

10tacle :

I took the cooler off, and applied a little bit of extra thermal paste, there was some air lines in between. And I've made sure it was well attached to the MB, it wasn't possible to tighten up anymore than that.
Here is a pic where I was monitoring while browsing internet and idling a little bit:

You can see that the temps vary depending on the CPU usage, but those peaks are like from 28c to 55c in a second, then it goes back to 30c.
The temps while idling are around 28c to 31c.
What botters me is that unstabble variance.

Gnuffi · Apr 20, 2016

Jun Ho :

background apps have been known to be able to do that, even to an idle gpu too,
a certain app could suddenly "want to use" either the cpu or gpu for a few seconds in such a way as if it was under load, causing the temps to rise
even tho i thought the days where apps behaved like that was over, it might just be it

since you've already rechecked the paste and fastened the cooler tightly as per 10tacle's instructions, try monitor apps cpu usage, and see if one of those are teh culprit, and if it is terminate the app
(since the spikes of temp seem to comply and accompany with rising load according to teh graph, which makes sense)
and remember, core temp respond extremely fast to variances, so tiny load will make your temps rise in a flash, and then quick down again
(how much they will and/or should rise in temp is another thing ofc, but if the load is decent, even for a few secs, 50c doesnt sound unreasonable to me, considering you're starting at around 30c)

Jun Ho · Apr 21, 2016

Gnuffi :

Thanks for your reply!
I think you are right, I just contacted Intel support and the representative said to me that those variations are normal, even like 30c to 50c in a blink of an eye.
She said to run a processor diagnostic, so I did, and the processor has passed on all the tests.
But here is a curious thing, at least for me.
Before I ran the test, you can clearly notice the variations that I'm worried about, going from 30c to 55c and so on.
However, while running the Intel test, you can see that the temps are stable as hell, they were around 59c - 61c, and didn't show any peaks.

Gnuffi · Apr 21, 2016

Jun Ho :

not only is that normal there is a quite simple explanation
when your cpu is idling its not "inactive" means its doing random small tasks, and some of them can as before mentioned cause a short spike
however once you actually get some load on teh cores, and a constant load at that, your temps will rise, yes, but the temps will remain more stable, because there is an even load

if you look at the load graph you see its steady like a rock, in teh exact same the stable load occurs time your cpu temps get stable and steady too, working as it should

cpu temps not only gets more stable under load and sustained "equal" load, but the temp readings even get more accurate
idle temps can often be very inaccurate

no worries at all

10tacle · Apr 21, 2016

Just remember that the best way to test your CPU cooling efficiency is to run it through an extended stress test (AIDA64, OCCT are the two I use). In this manner, any spike variations are ruled out as all four cores are loaded equally. And yes, even during idling there can be wide spike variations between the four cores. What you need to look for is variations between each core in temps while all are equally loaded out.

And again, if you see a variation approaching 10C with all four cores under load equally, then it's a cooler problem (either a mount problem, paste application problem, or defective CPU contact plate not machined perfectly flat as mentioned previously). In my experience, a poor mount job or defective heat sink will cause two cores to run consistently at different temps than the other two (like 47C, 48C, 56C, 57C). This can only be exposed though with a stress test run.

Gnuffi · Apr 21, 2016

10tacle :

while a completely agree
i think i just recently read that Intel actually says that core temp variances up to 10c is okay and within guidelines on teh 6700k
then again i have just recenlty been sifting through stacks of docs and sheets in order confirm my own current settings, so there is the chance i might have mixed data, but im somewhat sure thats what i read
still not thats its good, just that Intel says its "ok"..

10tacle · Apr 21, 2016

Gnuffi :

Yeah I saw that from an Intel rep in a thread here a while back. Someone with a Skylake i7 was complaining about idle spikes if I remember correctly. That's what the Intel rep was responding to. He/she was never specific on temp variation with all four cores under sustained load, which to me isn't good. That's why aftermarket software load tests are crucial....they generally run all cores at maximum 100% equally for an extended period, something that general real world load use, even gaming, would never see.

Jun Ho · Apr 21, 2016

Gnuffi :

I've run a test again using Intel Diagnostic Tool to check the core temps. And I think there isn't any noticeable variance between the cores/threads.
They were running at 95-100% while testing.

Thank you very much for sharing your opinions!
But the things get wild while gaming, temps going from 55c to 74c, 44c to 67c in a second. Even though the guy from Intel said it is normal, I'm still bugged by this.

Gnuffi · Apr 21, 2016

10tacle :

Gnuffi :

Yeah I saw that from an Intel rep in a thread here a while back. Someone with a Skylake i7 was complaining about idle spikes if I remember correctly. That's what the Intel rep was responding to. He/she was never specific on temp variation with all four cores under sustained load, which to me isn't good. That's why aftermarket software load tests are crucial....they generally run all cores at maximum 100% equally for an extended period, something that general real world load use, even gaming, would never see.

couldnt agree more with you

10tacle · Apr 21, 2016

Yes, gaming loads will never use all cores equally at all times, even games coded for such use of all four cores. The reasons are complex, but games may use one core for one thing, and other cores for other things. I've never used the Intel diagnostic tool, but if it really stressed your CPU as it claims it did equally across all threads, then your temp variations look fine...very good as a matter of fact.

Jun Ho · Apr 21, 2016

10tacle :

Just remember that the best way to test your CPU cooling efficiency is to run it through an extended stress test (AIDA64, OCCT are the two I use). In this manner, any spike variations are ruled out as all four cores are loaded equally. And yes, even during idling there can be wide spike variations between the four cores. What you need to look for is variations between each core in temps while all are equally loaded out.

And again, if you see a variation approaching 10C with all four cores under load equally, then it's a cooler problem (either a mount problem, paste application problem, or defective CPU contact plate not machined perfectly flat as mentioned previously). In my experience, a poor mount job or defective heat sink will cause two cores to run consistently at different temps than the other two (like 47C, 48C, 56C, 57C). This can only be exposed though with a stress test run.

I've captured a brief moment where there was actually a 10c+ difference between the cores.
Is that what you talking about

Gnuffi · Apr 21, 2016

Jun Ho :

that can be very very normal depending on game
since very few games will actually give a stable solid constant load
mine for instance not only spikes in load, it even switches cores, meaning 1 sec core 1 will spike to 70% load, then down to zero and core4 will jump up for a short
and as teh load varies and jumps up and down, so does teh temp
if you stress test in a real stress program and temps are fine, you will have aboslutely nothing to worry about
i run aida64+real bench, seperately then at teh same time, i dont use prime95 because well, bad rep lately version and even worse since i run in adaptive mode, would prob kill it

Elderblaze · Jul 24, 2016

You fan speeds on the cooler can have an impact on weird fluctuations as well, especially if your riding a break point. For example if your fan ramps up quickly once your CPU is 70 degree's and your sitting around 68-75 degree's your fan speeds are doing weird stuff, as soon as you jump to 75 degrees the fans ramp up and quickly put you back in the 60's and this cycle go's back and forth. Adjust fan profile

djtinxo · Sep 27, 2016

just mounted my pc (same enermax cooler) and searching along google I found this thread and had to share my opinion, because this bothers me too. It's not the 6700k temperature peaking, it's the case and cpu fans that ramp up very fast, thus being loud and making some weird air fluctuations. I just had to set the fan curve just between 60 and 70º to avoid this...

i7 6700k unstable temperatures

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