[SOLVED] Prime95 no AVX

Digicats

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I already know my AIO can't cool my CPU past where it currently is @ 4.6ghz 1.26v 8700k maximus x formula

I just need to know how to set up prime95 to just test for every day use stability. It goes 4 hours in OCCT with CPU, CACHE, and MEMORY checked with no issues. Checking FPU increases the temps and I hear prime is even worse. There's an older version I heard does this but I can't find it.
 

CompuTronix

Intel Master
Moderator
"Smallest" FFT's will be the same as "Small" FFT's. However, we use Small FFT's for simplicity and consistency among different versions so as to not create any more confusion than that which already exists.

Don't get discouraged or jump to conclusions. The reason your Core temperatures skyrocketed was strictly due to AVX. As I explained above, if you run Prime95 Small FFT's without AVX, your Core temperatures will be valid and conform to Intel's Datasheets. Anything more is an overload, and anything less is an underload.

“Stress” tests vary widely and can be characterized into two categories; stability tests which are fluctuating workloads, and thermal tests which are steady workloads. Prime95 v29.8 Small FFT's (AVX disabled) is ideally suited for testing thermal performance, because it conforms to Intel's Datasheets as a steady 100% workload with steady Core temperatures. No other utility can so closely replicate Intel's thermal test workload.

Utilities that don't overload or underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as thermal and stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:



Although these tests range from 70% to 130% TDP workload, Windows Task Manager interprets every test as 100% CPU Utilization, which is processor resource activity, not actual workload. Core temperatures respond directly to Power consumption (Watts), which is driven by workload. Prime95 v29.8 Small FFT’s (AVX disabled) provides a steady 100% workload, even when TDP is exceeded by overclocking. If Core temperatures don't exceed 85°C, your CPU should run the most demanding real-world workloads without overheating.

Give it a try with AVX2 and AVX disabled. Your Core temperatures shouldn't be any higher than RealBench.

If you'd like to try an 80% workload, then run CPU-Z > Bench > Stress CPU.

• CPU-Z - http://www.cpuid.com/softwares/cpu-z.html

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.

What is your ambient (room) temperature? The "standard" for normal ambient is 22°C or 72°F.

CT :sol:
 

CompuTronix

Intel Master
Moderator
Digicats,

The issue with Prime95 you "heard about" specifically refers to processors with "AVX" Instruction Sets, such as your 8700K. When any version of Prime95 with AVX code runs on AVX capable processors, it can impose an unrealistic 130% workload, which can adversely affect stability and severely overload your processor.

This is why BIOS has an "AVX Offset" (downclock) adjustment to compensate for the exceedingly high Core temperatures which are caused whenever the CPU encounters brutal AVX workloads imposed by certain utilities and scientific computational apps. Real-world software that uses AVX code, such as for rendering and transcoding, or some of the most recent games. do not impose extreme workloads.

Accordingly, as per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX.

See page 87, Section 5.1.1, Thermal Considerations: 8th and 9th Generation Intel® Core™ Processor Families Datasheet, Volume 1 - https://www.intel.com/content/www/us/en/products/docs/processors/core/8th-gen-core-family-datasheet-vol-1.html

Prime95 Small FFT's without AVX is ideally suited for testing thermal performance, because it conforms to Intel's Datasheets as a steady 100% workload with steady Core temperatures. No other utility can so closely replicate Intel's thermal test workload.

We have a "Sticky" for this topic at the top of the CPU's Forum: Intel Temperature Guide - https://forums.tomshardware.com/threads/intel-temperature-guide.1488337/

You might want to give it a read.

See Section 10 - Thermal Test Tools
See Section 11 - Thermal Test Basics

(Pre-AVX Version) Prime95 v26.6 - https://www.technic3d.com/download/overclocking-und-monitoring-tools/24-prime-95-v26.6.htm
Run only Small FFT's.

For Prime95 Version from 27.7 through 29.4, insert CpuSupportsAVX=0 into the local.txt file, which appears in Prime95's folder after the first run.

(Latest Version) Prime95 v29.8 - https://www.mersenne.org/download/
Click to disable AVX test selections in the following order; AVX2, AVX. Run only Small FFT's.



Core temperatures in Small FFT's are identical between pre-AVX version 26.6 and all later versions (27.7 through 29.8) with AVX disabled.

CT :sol:
 

Digicats

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Thanks for your replies. I'd like to not generate maximum heat. My cpu will never reach these high temps during normal use. During gaming I was only seeing about 76-78c and that was before I dialed the clock speed down to 4.6ghz. I just want to be safe, I can't afford to destroy this PC with unnecessary voltages and heat. There's a smallest FFTs option, would that be best?

Last time I ran small FFTs my cpu hit 90c in half a second on 4.4ghz 1.25v
 

Digicats

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Nevermind. I can't even run a realbench stress test without temps hitting 86c in the first 2 minutes. Need a better AIO.

Thanks anyways, I'll bookmark that info for use later.
 

CompuTronix

Intel Master
Moderator
"Smallest" FFT's will be the same as "Small" FFT's. However, we use Small FFT's for simplicity and consistency among different versions so as to not create any more confusion than that which already exists.

Don't get discouraged or jump to conclusions. The reason your Core temperatures skyrocketed was strictly due to AVX. As I explained above, if you run Prime95 Small FFT's without AVX, your Core temperatures will be valid and conform to Intel's Datasheets. Anything more is an overload, and anything less is an underload.

“Stress” tests vary widely and can be characterized into two categories; stability tests which are fluctuating workloads, and thermal tests which are steady workloads. Prime95 v29.8 Small FFT's (AVX disabled) is ideally suited for testing thermal performance, because it conforms to Intel's Datasheets as a steady 100% workload with steady Core temperatures. No other utility can so closely replicate Intel's thermal test workload.

Utilities that don't overload or underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as thermal and stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:



Although these tests range from 70% to 130% TDP workload, Windows Task Manager interprets every test as 100% CPU Utilization, which is processor resource activity, not actual workload. Core temperatures respond directly to Power consumption (Watts), which is driven by workload. Prime95 v29.8 Small FFT’s (AVX disabled) provides a steady 100% workload, even when TDP is exceeded by overclocking. If Core temperatures don't exceed 85°C, your CPU should run the most demanding real-world workloads without overheating.

Give it a try with AVX2 and AVX disabled. Your Core temperatures shouldn't be any higher than RealBench.

If you'd like to try an 80% workload, then run CPU-Z > Bench > Stress CPU.

• CPU-Z - http://www.cpuid.com/softwares/cpu-z.html

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.

What is your ambient (room) temperature? The "standard" for normal ambient is 22°C or 72°F.

CT :sol:
 

NightHawkRMX

Illustrious
What AIO do you have?

If one version of P95 makes your CPU in the 90s immediatly, the non-AVX version isn't going to fix the issue

If real bench is also in the high 80s, that's a sign of an unstable overclock thermally.
 
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Digicats

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TT floe riing 240mm It's a garbage cooler for OC. I figured that about Prime so I didn't run it. Both options say high heat which I can't do so I can't totally check for a stable OC. Just going to put it back to 4.4, cry, and then game.

Thanks again.
 
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