Question Thermal throttling as soon as I run Prime95

[ftpkmarcelo]

Hey guys, I'm trying to oc my 9700k and worker #6 keeps crashing in prime95 so I increase voltage but now im hitting thermal throttling as soon as i run prime 95 Cant even run the test now ,, I have a corsair h100x cooler.


I'm currently on 1.35v 4.9 Ghz all cores. I have a gigabyte z390 ud mobo, and vcore load line calibration is set to turbo.

 

[Darkbreeze]

Turn your LLC down to about midway, it does not need to be on turbo. That may help with the thermals.

So, make sure you are disabling AVX and AVX2 while thermal testing. Be sure to choose the "Small FFT" option, not "Smallest FFT".

You may simply not have a chip that is good enough for that OC, or a board that is not good enough for that chip to reach it's full potential. Not a great overclocking board to be honest.



Testing thermal compliance

Once you get to the Windows desktop, the first thing you will want to do is open HWinfo (Sensors only option) or CoreTemp and take a look at what your core and package temperatures are doing. At idle your core temps should be somewhere below 40°C. Preferably somewhere in the mid to low 30’s. This WILL be affected by whatever the ambient temperature is in the room where you are, so if your are in a very warm region and have no air conditioning going you may have an idle temp that is a bit closer to 40. For cooler ambient rooms or regions it will likely show low 30’s-ish. Be aware that unless you have excessively high idle temps, say, above 40°C, then what your actual idle temps are is practically irrelevant. Cooler idle temps are not indicative of much of anything specific.

Very HIGH idle temps however DO indicate that there is likely a problem with an incorrectly installed CPU cooler heatsink, too high of CPU core voltage or some other cooling or voltage related issue. If you are using one of those other utilities I warned about in the beginning of this tutorial, it may also be that the utility is reporting falsely. In that case, go get HWinfo or CoreTemp and check again.

If idle temps seem fine, then leave your monitoring application open and run Prime95 (Either version 26.6 or the latest version with AVX/AVX2 disabled).

Choose the Small FFT option (NOT "Smallest FFT") and allow it to run for fifteen minutes. If you are using the latest version of Prime95 (Version 29.8 or newer) then you NEED to be sure to disable the AVX and AVX2 options in the main options window. When you disable AVX2 the option to disable AVX will become available. If at any point your core or package temperatures exceed 80°C for Intel or AMD Ryzen platforms, then click the “Test” menu at the top of the Prime95 window and select “stop” or “exit”. Do not simply click the "X" in the top right corner as that will NOT stop the stress test, it will only minimize it to the tray.

You MUST click Stop or Exit from the drop down TEST menu at the top left of the window to stop the stress test.

CPU overclocking guide and tutorial for beginners

Covering the basics If you found your way here it's likely you are looking for help with basic overclocking. Either that or you're a long time overclocker interested in seeing whether I had any eye opening insights that you may have been lacking. Rest assured, I don't. This is only intended as...

forums.tomshardware.com

 

[mdd1963]

Is the CPU stable at stock clock speeds (two cores at 4.9 GHz, all cores at ~4.5 GHz?) , and auto/default core voltage? (Let's establish what it does temp-wise at stock behavior before the quest for all-core turbo at "x" speeds...; if a core faults at stock clocks, perhaps you have a partial case for warranty or RMA claims

Not all CPUs will maintain an all-cores at max turbo at default core voltage, and, it is certainly possible you own one with a 'weak core' that will not do it at 1.35V...(perhaps you dialing in/selecting 1.35V leaves only 1.295 at the CPU under extreme load? but, if there is already throttle action indicated, increasing core voltage seems fruitless)

Is this pump in question new, or, 3 years old and from a previous build? (Many pumps get hard water deposits/algae blockage after a few years)

 

[ftpkmarcelo]

This is a new build, it does fine in prime 95 with stock setting,
1.2v, temps stay at 86C and all workers work fine,
core1 49
core2 48
core3 48
core4 47
core5 47
core6 46
core7 46
core8 46

when i set LLC to turbo it keeps the voltage solid where i set it to, and 49x all cores doesn't seem to be a huge oc to be getting 100c so quick, if i set LLC to high (1 level below turbo) the voltage drops from 1.35 to 1.31, I wonder if this is a heat transfer issue or a setting that im missing, most people get the 9700k stable at 5ghz with 1.370v but not heat issues for what ive read online. Also I don't know how to turn AVX off in prime95 I don't see the option you mentioned. Thanks for replying.

 

[CompuTronix]

ftpkmarcelo,

When asking questions related to temperatures, in addition to providing full system specs, please always include ambient (room) temperature. Members write into our Forums every day who live anywhere from the Arctic Circle to the Equator, so ambient temperature might range anywhere from 10°C (50°F) to 40°C (104°F) or more, which can be a HUGE variable. Just so no one proceeds on false assumptions:

What is your ambient (room) temperature ?

The "standard" for normal ambient temperature is 22°C or 72°F, so for every degree ambient is higher, your Core temperatures will also be at least that much higher.

I don't know how to turn AVX off in prime95 I don't see the option you mentioned.

Which VERSION of Prime95 ?

If you're running the latest version, 29.8, then you should see:



Note: Click on the AVX test selections that are not greyed out so that all three AVX boxes are checked, as shown above.

As per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX”. In Prime95 versions from 27.7 through 29.4, AVX can be disabled by inserting CpuSupportsAVX=0 into the local.txt file, which appears in Prime95's folder after the first run. However, since Core temperatures will be the same as 29.8 without AVX, it's easier to just use 29.8. You can also use 26.6 which doesn't have AVX.

CT

 

[ftpkmarcelo]

Ok so i disable avx in prime95 and i was even able to lower the voltage to 1.3v @4.9ghz temps stayed at 91C , but how do i really test for stability without avx?, room temps is 21C

 

[CompuTronix]

My esteemed colleague, Darkbreeze, provided a link to his Overclocking Guide, which explains how to test for stability. I strongly suggest that you give it a read: https://forums.tomshardware.com/faq/cpu-overclocking-guide-and-tutorial-for-beginners.3347428/

CT

 

[Darkbreeze]

Also, the temps you are outlining at 85-91°C, are far too high to be acceptable for long time use, especially if you run anything that DOES use AVX instructions unless you're also using offsets for AVX. If you want to to fully understand what is acceptable and what is not, I'd suggest you read the Intel temperature guide linked to in Computronix signature. It is pretty much THE definitive guide on anything related to Intel temperatures and behaviors on their CPUs.

How To - Intel CPU Temperature Guide

Update: September 19th, 2024 Preface The topic of processor temperatures can be very confusing. Conflicting opinions based on misconceptions concerning terminology, specifications and testing leaves users uncertain of how to properly check cooling performance. This Guide provides an...

forums.tomshardware.com

 

[ftpkmarcelo]

well, 91c during a stress test should be acceptable or not?, because while gaming and having multiple programs runing, (discord, google chrome, etc,) even while straming the cpu temps don't go higher than 54C, I have really good case cooling fans and even my graphics card doesnt go over 60C while gaming at max setting (RTX 2070), its just prime95 the one that makes my cpu get really hot.

 

[Afro_ninja199]

well, 91c during a stress test should be acceptable or not?, because while gaming and having multiple programs runing, (discord, google chrome, etc,) even while straming the cpu temps don't go higher than 54C, I have really good case cooling fans and even my graphics card doesnt go over 60C while gaming at max setting (RTX 2070), its just prime95 the one that makes my cpu get really hot.

same here mate, i ran prime95 and shat my self with io saw the temps ( i overclocked my i7 8700k to 4.9Ghz at 1.26 ) while gaming etc temps are good,

 

[CompuTronix]

... 91c during a stress test should be acceptable or not?

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.



Core temperatures increase and decrease with ambient temperature. The "standard" for normal ambient (room) temperature is 22°C or 72°F.

... its just prime95 ... that makes my cpu get really hot.

There are several tests that will drive Core temperatures even higher than Prime95 Small FFT's without AVX. See below:



ftpkmarcelo and Afro_ninja199,

"Gaming" workloads are "fluctuating" workloads that vary greatly depending on how a particular game title allocates CPU / GPU workloads. This makes gaming a poor metric for measuring thermal performance because there's no "standard". As such, gaming workloads don't conform in any way to Intel's datasheets. We use Prime95 Small FFT's without AVX because it's a "steady" 100% TDP workload that does conform to the datasheets, which provide the standards we follow to perform a valid thermal test.

However, if your heaviest workloads are games, and you don't run, or have any intentions of running more demanding workloads such as rendering or transcoding which can approach or equal the workload of Prime Small FFT's without AVX, then although your thermal performance doesn't conform to the datasheets, it's certainly adequate for gaming. Also, keep in mind that 91°C hottest Core during Prime95 Small FFT's without AVX at 21°C ambient leaves very little headroom for higher seasonal indoor temperatures.

Moreover, a 240mm AIO is considered marginal for the 9700K as well as the 9900K; the principal difference being Hyper-Threading, which creates higher Core temperatures. We instead recommend a minimum AIO of 280mm, and preferably 360mm for these processors. Since all AIO's do and will eventually fail, keep this in mind when replacing your 240mm AIO down the road.

Darkbreeze suggested that you read the Intel Temperature Guide, so if you really want to get yourself up to speed on this topic, then I would do so: https://forums.tomshardware.com/threads/intel-temperature-guide.1488337/

CT

 

[Afro_ninja199]

Here's the nominal operating range for Core temperature:

Core temperatures above 85°C are not recommended.

Core temperatures below 80°C are ideal.



Core temperatures increase and decrease with ambient temperature. The "standard" for normal ambient (room) temperature is 22°C or 72°F.



There are several tests that will drive Core temperatures even higher than Prime95 Small FFT's without AVX. See below:



ftpkmarcelo and Afro_ninja199,

"Gaming" workloads are "fluctuating" workloads that vary greatly depending on how a particular game title allocates CPU / GPU workloads. This makes gaming a poor metric for measuring thermal performance because there's no "standard". As such, gaming workloads don't conform in any way to Intel's datasheets. We use Prime95 Small FFT's without AVX because it's a "steady" 100% TDP workload that does conform to the datasheets, which provide the standards we follow to perform a valid thermal test.

However, if your heaviest workloads are games, and you don't run, or have any intentions of running more demanding workloads such as rendering or transcoding which can approach or equal the workload of Prime Small FFT's without AVX, then although your thermal performance doesn't conform to the datasheets, it's certainly adequate for gaming. Also, keep in mind that 91°C hottest Core during Prime95 Small FFT's without AVX at 21°C ambient leaves very little headroom for higher seasonal indoor temperatures.

Moreover, a 240mm AIO is considered marginal for the 9700K as well as the 9900K; the principal difference being Hyper-Threading, which creates higher Core temperatures. We instead recommend a minimum AIO of 280mm, and preferably 360mm for these processors. Since all AIO's do and will eventually fail, keep this in mind when replacing your 240mm AIO down the road.

Darkbreeze suggested that you read the Intel Temperature Guide, so if you really want to get yourself up to speed on this topic, then I would do so: https://forums.tomshardware.com/threads/intel-temperature-guide.1488337/

CT

thank you for all the info on this

 

[Darkbreeze]

Yes, much thanks to Comp, because he has spend literally hundreds and hundreds of hours of work compiling and testing to give us that information and provide us with an outstanding source of reference for Intel platforms. Much love for that.

 

[Karadjgne]

OC is a theory on balance. Higher voltage = more work = higher temps. So the theory behind OC is getting the highest stable speeds for the lowest stable voltages. Just jacking up voltages defeats the purpose.
LLC is trixy. It's a pre-emptive voltage increase. As the cpu hits a load, voltage drops and because games etc use highly variable loads the peaks and drops get nuts. The difference is called vdroop.

When you are trying to minimize vcore, you get close to a low average voltage, barely enough for stability. Then you game and the voltage you set when the game hits hard isn't enough. Normally this would crash the cpu, not enough voltage, but LLC is designed to add a small amount of voltage right as the vdroop is going down. That small bump should be enough to offset the low vdroop, and your cpu gets enough voltage.

Setting LLC too high is just as bad as not enough. Now you are applying that voltage not only to the droop, but the peak as well. So you get a somewhat higher voltage than you'd like. Making the droop that much sharper of a drop. And you get instability.

Most OC will fall in the 50-66% range at best, or whatever is in the middle. Many smaller or slight OC can be left on auto or @ 25%. Turbo/extreme is usually reserved for those ppl pushing LN2, liquid nitrogen cooled cpus that are 2, 3, or even 4+GHz above stock levels.

 

[Darkbreeze]

Turbo/extreme is usually reserved for those ppl pushing LN2, liquid nitrogen cooled cpus that are 2, 3, or even 4+GHz above stock levels.

Which is exactly what I indicated earlier, so thanks for bringing that point back up and confirming the point. Since it seems it just got ignored in the mix.