7700k keeps throttling, driving me nuts...

NoxTek

The Geek Redneck
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So I've recently de-lidded my new 7700k and sofar the results have been amazing. I'm currently trying to get my rig to run stable at 5ghz with the lowest vCore I can get away with. But as I sit here running a small FFT job in Prime95, I'm watching the CPU core speed in CPUID and seeing it drop sporadically from 5000mhz to around 4200mhz.

In the BIOS I've disabled Speedstep, TurboBoost, and all C-states, set the TDP limits per core to 120w, enabled flex ratio override and set the multiplier on it to 50, disabled turbo boost, and of course the CPU multiplier is manually set to 50.

For some reason, at random while under load, the CPU multiplier seems to be dropping to 42x (the stock multiplier for the 7700k). vCore is currently set to 1.39v and LLC is set to 'high' in the UEFI. Core temps on all four cores average in the mid 60s across the board so I don't think it's a thermal throttling issue.

I'm trying to figure out what I could be missing here...

System stats are in the sig, UEFI version on the Gigabyte Z170MX Gaming 5 is F22a (the latest official release).

Anyone have any insights?


[EDIT: Using TechPowerUp's excellent 'ThrottleStop' utility, it appears that my throttling seems to be coming from reaching a thermal limit on voltage regulators ... somewhere. Maybe the poor Z170 can't handle o/cing Kaby Lake to it's full potential, or Gigabyte used crappy TIM on the VRM heatsinks? I can't find anywhere in the BIOS where this particular thermal limit can be disabled or adjusted so I'm assuming it's something hard coded - probably to keep the mobo from roasting. :D]

upload_2017-11-11_10-45-30.png



A little info on cooling:

Base case configuration is a Thermaltake Core v21 (Micro ATX cube style chassis). Huge 200mm fan in the front doing intake duties, a 140mm rear doing exhaust. CPU cooling is a Thermaltake Floe Riing Edition 240 AIO/CLC, with the 240mm rad mounted in the left side of the case (nearest the CPU) and the two 120mm fans pushing through the rad and out of the left side of the case.
 
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NoxTek

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Sounds like some kinda of throttling due to AVX loads, be it thermal or power related. Use a non-AVX synthetic test and see if it exhibits the same symptoms.

Recommendations on a specific test or tests? Thanks for your assistance and any input! :)
 

kirbyrj

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There's no TIM on the VRM heatsinks...probably just a thermal pad. I'd put a fan on the VRM heatsink and see what happens.
 

NoxTek

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There's no TIM on the VRM heatsinks...probably just a thermal pad. I'd put a fan on the VRM heatsink and see what happens.

Oh yeah, I'm sure it's just 3M thermal adhesive tape or something along those lines. The 'heatsinks' on the VRMs are more for looks and flash than they are for functionality, I'm sure. I suppose I'll try aiming some additional temporary airflow that way and see if it changes anything. At least that way I could confirm that that is indeed the issue - I could be totally wrong and chasing my tail here.
 
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Well can you try having the top fans blowing down on the VRMs? I know it's not optimal but that's a drawback of buying these tiny cases and having everything packed in so tightly.
 

NoxTek

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Well can you try having the top fans blowing down on the VRMs? I know it's not optimal but that's a drawback of buying these tiny cases and having everything packed in so tightly.

I just got a fit of the giggles because I know in a box in the garage I have a bunch of these insane 120mm x 38mm 100cfm fans from an Ebay deal awhile back.... :D

Of course I have other more sensible (and quiet) options, like the excellent Noctua fans off my old NH-D15.
 
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Yeah it can be difficult sometimes to get good airflow on the VRMs depending on case design. I looked at your mobo and it does have those push-pin ones which I'm not a fan of. Screws are much more secure/tight.
 

chameleoneel

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I wouldn't worry about it. Prime 95 stresses your CPU beyond any work load you will realistically do.

I prefer encoding a movie in handbrake. It's a real workload and it's something I do fairly often.

you can run a gpu benchmark at the same time, as well. Like furmark or one of the final fantasy benchmarks.
 

NoxTek

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UPDATE: I've tried putting a fan near / over the VRM / CPU socket area on the motherboard and no dice, it still starts to periodically throttle to the CPU's default multiplier (42x) after about two minutes.

Meh, I'm going to do some video encoding in Sony (err... MAGIX) Vegas Pro and see how things behave under a more 'realistic' load scenario, but it's just one of those things that bugs the heck outta me. Especially not knowing if it's for sure because of VRM overheating, or maybe just some artificial thermal / power cap setting I've overlooked in the BIOS/UEFI somewhere.
 

NoxTek

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Just a final update (unless someone comes up with more ideas to try):

  • Tried bumping the vCore up all the way to 1.43 volts (I know that Skylake and Kaby Lake can handle up to 1.45 pretty safely) and it made no difference.
  • Backed the multiplier down to 49x and it runs happy as a pig in shit - hours and hours of small FFTs in Prime95 or ASUS Realbench and not a sign of throttling.

I guess I'm just going to have to come to terms that I'm not going to reach the mythical 5ghz goalpost and have it not throttle under (admittedly artificial) stress tests.

I'm thinking more and more that it's this Gigabyte Z170MX Gaming 5 that's the limiting factor and not the 7700k. :)
 

BitMaster

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Wow...1.45V...?? That's a hefty load for that CPU.

It should hover at 5G with ~1.300V for daily use ( incl. Handbrake ) and may need up to 1.350V for a full AVX load with prime95.


I also think your MSI board sucks. My MSI M9 Gaming ACK was also a looser. It clocked my 6700k only to 4.4 on all cores before collapsing. Same CPU on an Asus M9E went 4.7 directly without any glitches.

If you need more than 1.400V to have a stable 5G on a DELIDDED CPU something is badly wrong imho
 

mda

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Just a final update (unless someone comes up with more ideas to try):

  • Tried bumping the vCore up all the way to 1.43 volts (I know that Skylake and Kaby Lake can handle up to 1.45 pretty safely) and it made no difference.
  • Backed the multiplier down to 49x and it runs happy as a pig in shit - hours and hours of small FFTs in Prime95 or ASUS Realbench and not a sign of throttling.

I don't have a modern chip, but I remember around 1.5V being thrown out as the threshold for those Q6600 chips before any degradation... Using this value, the conclusion I have jumped to is... Unless you replace your chips pretty often I don't think 1.45V is safe for Skylake/Kaby.
 

NoxTek

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Wow...1.45V...?? That's a hefty load for that CPU.

As I said, I had just bumped the vCore up to 1.43, and again just for a few minutes to test a theory. :)

It should hover at 5G with ~1.300V for daily use ( incl. Handbrake ) and may need up to 1.350V for a full AVX load with prime95.

Interesting, considering [H]'s own 7700k needed something like 1.36v to run fully stable at 5ghz if I recall correctly...

I also think your MSI board sucks. My MSI M9 Gaming ACK was also a looser. It clocked my 6700k only to 4.4 on all cores before collapsing. Same CPU on an Asus M9E went 4.7 directly without any glitches.

I'd think if I had an MSI board it probably WOULD suck hard... at least harder than the GIGABYTE board I've referred to in this thread all along. ;) For the record, it's a Gigabyte Z170MX Gaming 5. :D

If you need more than 1.400V to have a stable 5G on a DELIDDED CPU something is badly wrong imho

Maybe... as I understand it not EVERY 7700k reaches 5ghz stable no matter how much vCore you throw at it. Sure, you stand a higher chance than you did with Skylake but still...



Anyway, as it stands the system (again, stats in the sig) seems pretty damned happy at 4.9ghz. That's with 1.300 vCore set in the BIOS and 1.284v showing up under extreme load in CPUID / HWINFO. I'm thinking that's nothing to sneeze at for sure. :)
 
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NoxTek

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Thought I'd update this thread...

My 7700k just will not do 5ghz on this board. I honestly think it's the board (Gigabyte Z170MX Gaming 5) and not the CPU itself holding things back. At 5ghz with enough vCore to keep it stable, it eventually starts to throttle to 4.2ghz and again the only clue I have is via the ThrottleStop tool, which gives indications of some sort of thermal throttling for voltage regulation SOMEWHERE. CPU core temps during all of the above never leave the lower 70s.

I HAVE however, found a very happy medium at 4.9ghz. At 4.9ghz with a core voltage around 1.28v this thing will run small FFTs in Prime95 or ASUS RealBench all damn day no sweat. That's with no signs of the above throttling either - rock solid 4900mhz all throughout. That's what makes me think this 7700k itself has loads more to give, and that it's the Z170 board that's holding me back.

Anyone got recommendations on a Z270 micro ATX board that's got good overclocking prowess?
 

jfreund

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I agree that it's your board. I had a Gigabyte Z170 Gaming 5 that did the exact same thing. It would limit the CPU power draw and throttle cores down under load. I returned the board and got an Asrock Z170 Formula that has been great. My 6700K has been happily running 4.8GHz @ 1.35V for almost 2 years with an H115i.
 

Speedeu4ia

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Thought I'd update this thread...

My 7700k just will not do 5ghz on this board. I honestly think it's the board (Gigabyte Z170MX Gaming 5) and not the CPU itself holding things back. At 5ghz with enough vCore to keep it stable, it eventually starts to throttle to 4.2ghz and again the only clue I have is via the ThrottleStop tool, which gives indications of some sort of thermal throttling for voltage regulation SOMEWHERE. CPU core temps during all of the above never leave the lower 70s.

I HAVE however, found a very happy medium at 4.9ghz. At 4.9ghz with a core voltage around 1.28v this thing will run small FFTs in Prime95 or ASUS RealBench all damn day no sweat. That's with no signs of the above throttling either - rock solid 4900mhz all throughout. That's what makes me think this 7700k itself has loads more to give, and that it's the Z170 board that's holding me back.

Anyone got recommendations on a Z270 micro ATX board that's got good overclocking prowess?

I have a 7700k on z270 gigabyte gaming 5 itx board. The voltage is screwy, Never seen Vcore jump as much as it does while stressing. It overvolts on auto or normal, then again when I raise the LLC from normal. Since I'm using offset(DVID) and want to keep idle states I end up with 4.8GHZ with -.065v which under load gives me 1.27-1.29 VCORE(stilll dont understand why "normal" vcore is 1.34v, and they even had a bios update to fix overvolting). Basically anything I try to change makes it go above 1.32v even with it set at the -.065v offset(ant 4.9 is still not stable). Seems this is somewhat common and broken on a few z170/270 boards and all gigabytes
 
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JNavy89GT

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yeah my Gigabyte Z170 board did that as well with my 6600k. Was the VRM's and even with active cooling it would still throttle. Finally just got a different board :(. Probably doesn't really effect performance that much, but it annoyed me.
 

FrgMstr

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Thought I'd update this thread...

My 7700k just will not do 5ghz on this board. I honestly think it's the board (Gigabyte Z170MX Gaming 5) and not the CPU itself holding things back. At 5ghz with enough vCore to keep it stable, it eventually starts to throttle to 4.2ghz and again the only clue I have is via the ThrottleStop tool, which gives indications of some sort of thermal throttling for voltage regulation SOMEWHERE. CPU core temps during all of the above never leave the lower 70s.

I HAVE however, found a very happy medium at 4.9ghz. At 4.9ghz with a core voltage around 1.28v this thing will run small FFTs in Prime95 or ASUS RealBench all damn day no sweat. That's with no signs of the above throttling either - rock solid 4900mhz all throughout. That's what makes me think this 7700k itself has loads more to give, and that it's the Z170 board that's holding me back.

Anyone got recommendations on a Z270 micro ATX board that's got good overclocking prowess?
Have not gone through this entire thread, but have you used HWINFO to see if you can tell why it is throttling? There are some fields there that are specific to throttling.
 
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