I ran Prime95 for 5 hours on my non-OC Haswell i7 4790k.

[Temoojin]

Hi Guys,

I was using Prime95 on Blend mode for 5 or so hours to see my CPU temperatures under load until I read that the testing software can damage my system?

If I didn't Overclock my i7 4790k yet, could my CPU have been damaged?

Thank you.

EDIT: I didn't use the previous version (26.6?) as recommended for older CPU generations like mine

 

[Darkbreeze]

Testing software does not damage systems. Running testing software after you've already seen that it is overheating due to a lack of correct or sufficient cooling, THAT can damage a system.

Blend mode is the wrong test anyhow. I only advise using Prime95 version 26.6, and ONLY version 26.6, and ONLY on the Small FFT option, which presents a STEADY STATE load to the CPU and is the correct method of testing for thermal compliance AND baseline stability testing.

Your CPU is fine, or at least, is not damaged from running Prime95 although I would not run versions newer than 26.6 anymore unless you are an advanced user who KNOWS that you will be using applications that use AVX instructions and need to verify thermal compliance when doing so. At the stock configuration, even that should not be a problem anyhow though.

THIS.

Prime95 v26.6 is THE primarily accepted way to do the majority of baseline stability and thermal limit testing running the Small FFT option.

Prime95 Version 26.6 download


Further, you can find extensive information regarding the Intel CPU architectures and specifications at the following link which is a somewhat definitive guide on that subject. The information below is taken directly from conversations with Computronix who is also the author of the Intel temperature guide, found here:

The Intel temperature guide

For AMD systems, specifically Zen/Ryzen, this should offer similar albeit not nearly as detailed information on that architecture.

Ryzen overclocking guide

This is probably about the most referred to overclocking guide around, and it's principles can be applied to a variety of generations and platforms.

The Ultimate Overclocking Guide



This pretty well sums things up and is equally relevant whether working with an Intel or an AMD system.

I can think of several reasons why x264 encoding or AVX / AVX2 / FMA3 apps won't work as a unilateral metric for thermal testing.

(1) A steady-state workload gives steady-state temperatures; encoding does not.

(2) Simplicity in methodology; most users would find encoding apps unfamiliar and cumbersome to accomplish a simple task.

(3) Most users such as gamers never run any apps which use AVX or FMA, so adaptive or manual voltage aside, it makes no sense to downgrade your overclock to accommodate those loads and temps unless you KNOW you will be making significant use of AVX/FMA/AVX2.

(4) Standardization; Prime95 has been around since 1996; many users are familiar with it. It is TRIED and TRUE.

For the minority of users who routinely run AVX/FMA apps, then P95 v28.5 or later can be useful for tweaking the BIOS for thermal and stability testing on THOSE types of systems only. For others, it is not recommended.


regardless of platform or architecture, Prime95 v26.6 works equally well across ALL platforms. Steady-state is the key. How can anyone extrapolate accurate core temperatures from workloads that fluctuate like a bad day on the stock market? They can't. That's why steady state is necessary for testing of thermal compliance and for baseline stability verification.

I'm aware of 5 utilities with steady-state workloads. In order of load level they are:

(1) Prime95 v26.6 - Small FFT's (Important. NOT Blend or Large FFT)
(2) HeavyLoad - Stress CPU
(3) FurMark - CPU Burner
(4) Intel Processor Diagnostic Tool - CPU Load
(5) AIDA64 - Tools - System Stability Test - Stress CPU

AIDA64's Stress CPU fails to load any overclocked / overvolted CPU to get anywhere TDP, and is therefore useless, except for giving naive users a sense of false security because their temps are so low.

HeavyLoad is the closest alternative. Temps and watts are within 3% of Small FFT's.

-Computronix

 

[lumineZ]

No it is not damaged so long as you have enough cooling power.

Read the best answer from this topic since it has been "answered"
http://www.tomshardware.co.uk/answers/id-3382407/version-prime95-kaby-lake.html

 

[Temoojin]

Testing software does not damage systems. Running testing software after you've already seen that it is overheating due to a lack of correct or sufficient cooling, THAT can damage a system.

Blend mode is the wrong test anyhow. I only advise using Prime95 version 26.6, and ONLY version 26.6, and ONLY on the Small FFT option, which presents a STEADY STATE load to the CPU and is the correct method of testing for thermal compliance AND baseline stability testing.

Your CPU is fine, or at least, is not damaged from running Prime95 although I would not run versions newer than 26.6 anymore unless you are an advanced user who KNOWS that you will be using applications that use AVX instructions and need to verify thermal compliance when doing so. At the stock configuration, even that should not be a problem anyhow though.

THIS.

Prime95 v26.6 is THE primarily accepted way to do the majority of baseline stability and thermal limit testing running the Small FFT option.

Prime95 version 26.6: http://windows-downloads-center.blogspot.com/2011/04/prime95-266.html


Further, you can find extensive information regarding the Intel CPU architectures and specifications at the following link which is a somewhat definitive guide on that subject. The information below is taken directly from conversations with Computronix who is also the author of the Intel temperature guide, found here:

http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

For AMD systems, specifically Zen/Ryzen, this should offer similar albeit not nearly as detailed information on that architecture.

http://www.overclockers.com/amd-ryzen-overclocking-guide/

This is probably about the most referred to overclocking guide around, and it's principles can be applied to a variety of generations and platforms.

http://www.overclock.net/t/91/ultimate-overclocking-guide

This pretty well sums things up and is equally relevant whether working with an Intel or an AMD system.

I can think of several reasons why x264 encoding or AVX / AVX2 / FMA3 apps won't work as a unilateral metric for thermal testing.

(1) A steady-state workload gives steady-state temperatures; encoding does not.

(2) Simplicity in methodology; most users would find encoding apps unfamiliar and cumbersome to accomplish a simple task.

(3) Most users such as gamers never run any apps which use AVX or FMA, so adaptive or manual voltage aside, it makes no sense to downgrade your overclock to accommodate those loads and temps unless you KNOW you will be making significant use of AVX/FMA/AVX2.

(4) Standardization; Prime95 has been around since 1996; many users are familiar with it. It is TRIED and TRUE.

For the minority of users who routinely run AVX/FMA apps, then P95 v28.5 or later can be useful tweaking BIOS for thermal and stability testing. For others, it is not recommended.


regardless of architecture Prime95 v26.6 works equally well across ALL platforms. Steady-state is the key. How can anyone extrapolate accurate Core temperatures from workloads that fluctuate like a bad day on the Stock Market?

I'm aware of 5 utilities with steady-state workloads. In order of load level they are:

(1) Prime95 v26.6 - Small FFT's (Important. NOT Blend or Large FFT)
(2) HeavyLoad - Stress CPU
(3) FurMark - CPU Burner
(4) Intel Processor Diagnostic Tool - CPU Load
(5) AIDA64 - Tools - System Stability Test - Stress CPU

AIDA64's Stress CPU fails to load any overclocked / overvolted CPU to get anywhere TDP, and is therefore useless, except for giving naive users a sense of false security because their temps are so low.

HeavyLoad is the closest alternative. Temps and watts are within 3% of Small FFT's.

Thank you for your detailed response.
I was monitoring CPU Temp with HWMonitor and Max didn't exceed 80C. Would you say this was "overheating" the CPU?

 

[lumineZ]

No you are safe. Its hot but safe.
The CPU you have does not throttle until it hits 100 degree celcius.

 

[Darkbreeze]

Pretty close. More than 80 is where throttling is likely to start happening. In this case you are probably ok but retest using the correct utility and version AND get rid of HWmonitor.


First of all, uninstall Open Hardware monitor. Don't ever use that OR HWmonitor. They are both grossly inaccurate on certain chipsets or with some specific sensors. Overall, they are junk programs mostly. Use HWinfo or CoreTemp.

CoreTemp is great for just CPU thermals. HWinfo is great for pretty much EVERYTHING else, including CPU thermals, core loads, core temps, package temps, GPU sensors, HDD and SSD sensors, motherboard chipset and VRM sensor, all of it. Always select the "Sensors only" option when running HWinfo.

In order to help you, it's often necessary to SEE what's going on, in the event one of us can pick something out that seems out of place, or other indicators that just can't be communicated via a text only post. In these cases, posting an image of the HWinfo sensors or something else can be extremely helpful. Here's how:

*How to post images in Tom's hardware forums



Run HWinfo and look at system voltages and other sensor readings.

Monitoring temperatures, core speeds, voltages, clock ratios and other reported sensor data can often help to pick out an issue right off the bat. HWinfo is a good way to get that data and in my experience tends to be more accurate than some of the other utilities available. CPU-Z, GPU-Z and Core Temp all have their uses but HWinfo tends to have it all laid out in a more convenient fashion so you can usually see what one sensor is reporting while looking at another instead of having to flip through various tabs that have specific groupings.

After installation, run the utility and when asked, choose "sensors only". The other window options have some use but in most cases everything you need will be located in the sensors window. If you're taking screenshots to post for troubleshooting, it will most likely require taking three screenshots and scrolling down the sensors window between screenshots in order to capture them all.

*Download HWinfo


For temperature monitoring only, I feel Core Temp is the most accurate and also offers a quick visual reference for core speed, load and CPU voltage:

*Download Core Temp

When it comes to temperature issues, taking care of the basics first might save everybody involved a lot of time and frustration. Check the CPU fan heatsink for dust accumulation and blow or clean out as necessary. Avoid using a vacuum if possible as vacuums are known to create static electricity that can, in some cases, zap small components. Other areas that may benefit from a cleaning include fans, power supply internals, storage and optical drives, the motherboard surfaces and RAM. Keeping the inside of your rig clean is a high priority and should be done on a regular basis using 90 psi or lower compressed air from a compressor or compressed canned air.

Use common sense based on what PSU your compressor is set to. Don't "blast" your motherboard or hardware to pieces. Start from an adequate distance until you can judge what is enough to just get the job done. When using canned air use only short blasts moving from place to place frequently to avoid "frosting" components.

 

[Temoojin]

Thank you both for your replies!

 

[Darkbreeze]

You are welcome. If you have related, specific questions that were not answered by any of the preceding information, feel free to ask. Good luck.

Let us know if you get better results using HWinfo/CoreTemp and version 26.6 Small FFT, because if you STILL have thermal issues, we may need to address a less than satisfactory cooler mount or other issue.

 

[Temoojin]

One more thing, I'm downloading the 26.6 version of Prime95 but will I be using the 64bit download if my system is 64bit?

 

[Darkbreeze]

If you have a 64bit system, I would use the 64bit version of the utility.

 

[Temoojin]

That is after 10 minutes of torture testing (CPU Loading 100%) with Prime95 26.6 Small FTTs. Would you say these numbers are good/bad?

Thanks.

 

[Darkbreeze]

Seems a bit high too me, for not being overclocked. My 6700k overclocked to 4.5Ghz full time hits just about those same numbers. Your ALL core turbo speed, even running Prime, can't be 4.5Ghz on all cores so your thermals should be a bit better but are certainly within tolerance. There is room for cooling improvement but you are unlikely to see anything close to that in normal use, even gaming or running most applications.

 

[Temoojin]

Seems a bit high too me, for not being overclocked. My 6700k overclocked to 4.5Ghz full time hits just about those same numbers. Your ALL core turbo speed, even running Prime, can't be 4.5Ghz on all cores so your thermals should be a bit better but are certainly within tolerance. There is room for cooling improvement but you are unlikely to see anything close to that in normal use, even gaming or running most applications.

Do you know what could be causing the thermal increases? I have just installed a Corsair H115i AIO too.
Outside weather here was around 27 Celcius.

Could it be the seating of the CPU Block/improper Thermal paste contact? If not what else could be causing the increase in temperature for my non-OC i7 4790k?

Thanks again!

 

[Darkbreeze]

USUALLY on these, it's because there is a little bit of slop in the fastening of the backplate to the standoff screws. Motherboards are not all the same thickness, so less expensive boards are often thinner than higher end boards, which means that between two boards there can be a difference in how tight the whole assembly can be made using identical fasteners. This isn't always the problem, might just be that you didn't tight it ENOUGH, but don't overtighten and break something either.

Putting a small plastic washer between all four of the holes the bolts go through on the backing place and the backside of the motherboard, to actually move the backing place just a tiny bit further away from the motherboard so the standoff to bolt distance doesn't bottom out, resolved the problem.

In other words, spacers (small plastic washers) between the backing plate and motherboard. That allows the whole standoff to backing plate assembly to be firmly fastened down flat to the hardware side of the motherboard, rather than there being bottomed out fasteners that aren't actually FULLY seated, which in turn can cause there to be a little bit of looseness when you fasten down the water block to the top of the standoff and ends up not allowing there to be the right amount of mounting pressure between the top of the CPU lid and the water block/cold plate.

If you don't understand what I'm saying I can try to get an image/diagram to make it clear.


It WILL mean completely cleaning off the CPU lid and cold plate/water block using isopropyl alcohol and reapplying new paste though.

 

[Temoojin]

USUALLY on these, it's because there is a little bit of slop in the fastening of the backplate to the standoff screws. Motherboards are not all the same thickness, so less expensive boards are often thinner than higher end boards, which means that between two boards there can be a difference in how tight the whole assembly can be made using identical fasteners. This isn't always the problem, might just be that you didn't tight it ENOUGH, but don't overtighten and break something either.

Putting a small plastic washer between all four of the holes the bolts go through on the backing place and the backside of the motherboard, to actually move the backing place just a tiny bit further away from the motherboard so the standoff to bolt distance doesn't bottom out, resolved the problem.

In other words, spacers (small plastic washers) between the backing plate and motherboard. That allows the whole standoff to backing plate assembly to be firmly fastened down flat to the hardware side of the motherboard, rather than there being bottomed out fasteners that aren't actually FULLY seated, which in turn can cause there to be a little bit of looseness when you fasten down the water block to the top of the standoff and ends up not allowing there to be the right amount of mounting pressure between the top of the CPU lid and the water block/cold plate.

If you don't understand what I'm saying I can try to get an image/diagram to make it clear.


It WILL mean completely cleaning off the CPU lid and cold plate/water block using isopropyl alcohol and reapplying new paste though.

I have the ASRock Z97X Killer Mobo which I thought was a higher-end mobo.
I will see what happens when i correct this.
Thank you so much!!!

EDIT: But why take off the CPU lid? I have always just cleaned the thermal compound off the locked in position in the mobo. Should I be taking it out every time?

Also, quoting another TH user "if your 4790K is on a z87 or z97 board it will turbo mode automatically so it can run up to 4.520"

Does that mean it in fact does go up to 4.5 on load due to my specific Mobo?

 

[Darkbreeze]

You need to not worry about Turbo mode. It is NORMAL behavior, designed to work that way. It is not something extra that you add or that should not happen. It is SUPPOSED to happen. If you CANNOT allow that normal behavior, then you have OTHER problems. Turning off Turbo is a band aid to fix something else that is wrong temporarily. It is not a SOLUTION to the problem.

If you have to manually throttle the CPU, which is what turning off Turbo would be doing, then you are just avoiding whatever the actual problem is.


You do not "take off" the CPU lid. When you take off the cooler you clean the top of the CPU to remove the thermal paste that was applied during the previous installation. You cannot use the same thermal paste more than once. It needs to be cleaned off the CPU and off the bottom of the cooler where it contacts the CPU. Otherwise you WILL get air bubbles and poor coverage and you WILL have problems.

If you have reused the same thermal paste after removing the cooler on previous occasions, then THAT is likely your problem.

 

[Temoojin]

You need to not worry about Turbo mode. It is NORMAL behavior, designed to work that way. It is not something extra that you add or that should not happen. It is SUPPOSED to happen. If you CANNOT allow that normal behavior, then you have OTHER problems. Turning off Turbo is a band aid to fix something else that is wrong temporarily. It is not a SOLUTION to the problem.

If you have to manually throttle the CPU, which is what turning off Turbo would be doing, then you are just avoiding whatever the actual problem is.


You do not "take off" the CPU lid. When you take off the cooler you clean the top of the CPU to remove the thermal paste that was applied during the previous installation. You cannot use the same thermal paste more than once. It needs to be cleaned off the CPU and off the bottom of the cooler where it contacts the CPU. Otherwise you WILL get air bubbles and poor coverage and you WILL have problems.

If you have reused the same thermal paste after removing the cooler on previous occasions, then THAT is likely your problem.

Hi again darkbreeze,

I never re-used thermal paste but I did just today reapply and reseat the CPU cooler with new paste.

Trouble is, my temperatures have only increased. Now within minutes it reaches 70C+ with Prime 95 26.6 Small FTTs.

But I also changed my stock H115i AIO fans with the ML140s which supposedly provides same performance without the noise.

Lastly, I checked the backplate and its standoffs and they seem to be well secured without play with block screwed onto CPU.

Any ideas? Could it be that it is just an old CPU?

 

[Darkbreeze]

How much thermal paste are you using and EXACTLY what method are you using to apply it? Using too little or too much thermal interface material can definitely cause poor temps just the same as having poor mounting pressure can.

Also, please outline the exact configuration of your entire cooling system. How many fans. Where every fan is located and in what direction the airflow of that fan is actually moving air is.

Check the manufacturer product page for bios updates. Update to any version that is prior to December 2017. Do not install any version that is newer than that, as it is probably related to the recent Spectre and Meltdown vulnerabilities and likely has been recalled due to faulty, error riddled microcode. Prior to December though is fine and might result in changes to the stock voltage behavior of the default CPU management profile.

Check the bios to see what the vCore CPU voltage is set to.

Also check the RAM speed and voltage settings. Report both of those back here.

Being an "old" CPU is unlikely to have anything to do with it. CPUs can run and run and run, for years and years. They don't usually just suddenly start getting warmer because they've grown long gray beards and are using a cane to hobble along.

 

[Temoojin]

How much thermal paste are you using and EXACTLY what method are you using to apply it? Using too little or too much thermal interface material can definitely cause poor temps just the same as having poor mounting pressure can.

Also, please outline the exact configuration of your entire cooling system. How many fans. Where every fan is located and in what direction the airflow of that fan is actually moving air is.

Check the manufacturer product page for bios updates. Update to any version that is prior to December 2017. Do not install any version that is newer than that, as it is probably related to the recent Spectre and Meltdown vulnerabilities and likely has been recalled due to faulty, error riddled microcode. Prior to December though is fine and might result in changes to the stock voltage behavior of the default CPU management profile.

Check the bios to see what the vCore CPU voltage is set to.

Also check the RAM speed and voltage settings. Report both of those back here.

Being an "old" CPU is unlikely to have anything to do with it. CPUs can run and run and run, for years and years. They don't usually just suddenly start getting warmer because they've grown long gray beards and are using a cane to hobble along.

Thermal paste:
Using the line method as recommended by the manufacturer (Arctic Silver 5). I think I have used just enough. Although, they also mention a break-in time of 200 hours.. I doubt that that can make up for the heat I'm generating though.

Fans:
- Front Intake 3 x 120mm (came with case NZXT H440)
- Rear Exhaust 1 x 140mm (NZXT H440)
- Top Exhaust 2 x 140mm (on Corsair H115i AIO radiator)

BIOS: No post-2016 BIOS update available.
RAM speed: 1600MHz
RAM voltage:1.5
Vcore CPU voltage:1.072

 

[Darkbreeze]

Yeah, break in is for thermals to hopefully get BETTER, not GOOD. Should be GOOD from the start if everything is right and there are no issues.

Break in is definitely not your issue.

So, what BIOS version do you actually have installed?

What is the idle temperature of your CPU after five minutes of inactivity, just letting it sit there, once Windows has loaded up the desktop?

And again after five minutes of running Small FFT?

 

[Temoojin]

Yeah, break in is for thermals to hopefully get BETTER, not GOOD. Should be GOOD from the start if everything is right and there are no issues.

Break in is definitely not your issue.

So, what BIOS version do you actually have installed?

What is the idle temperature of your CPU after five minutes of inactivity, just letting it sit there, once Windows has loaded up the desktop?

And again after five minutes of running Small FFT?

BIOS version says 16/09/2014.

Idle temp hangs around around 26-30:

with Prime95 26.6 Small FTTs running for 5 minutes the cores had 71C 70C 67C 64C as max. values.

When running prime95, the "default" setting CPU Cooler radiator fan speed hovers around 900-1000 on prime95 load. There is an option to change this mode to "performance" upon which it ramps up to 1200-1300rpm. Should I leave the fans in performance setting?

 

[Darkbreeze]

That is a VERY old bios version. I suggest you should update to version 2.5 from 2016. It is the most recent listed version. BIOS updates for your board are located here:

https://www.asrock.com/MB/Intel/Fatal1ty%20Z97X%20Killer/index.asp#BIOS


I would set up a custom curve for the fans. I would use neither silent nor performance. Custom curves can better be tailored for both good performance when needed but also quiet the rest of the time. Or at least, quiet-ER anyhow. Never going to exactly be "quiet" with an AIO water cooler. Pumps and fans will always be somewhat noisy.


https://www.youtube.com/watch?v=OXKqhFe06Sw

 

[Temoojin]

That is a VERY old bios version. I suggest you should update to version 2.5 from 2016. It is the most recent listed version. BIOS updates for your board are located here:

https://www.asrock.com/MB/Intel/Fatal1ty%20Z97X%20Killer/index.asp#BIOS


I would set up a custom curve for the fans. I would use neither silent nor performance. Custom curves can better be tailored for both good performance when needed but also quiet the rest of the time. Or at least, quiet-ER anyhow. Never going to exactly be "quiet" with an AIO water cooler. Pumps and fans will always be somewhat noisy.


https://www.youtube.com/watch?v=OXKqhFe06Sw

So I am safe to disregard their warning on updating BIOS?

Just to double check.

 

[Darkbreeze]

I didn't say anything about being "safe". It's never "safe" to update the bios. There is always some risk involved. But if your system is stable enough that it does not crash or shut down while you are in the bios, no matter how long you are in the bios, then it should be fine. If you have problems with it shutting down or crashing while in the bios then definitely you have a bigger problems.