Noctua IndustrialPPC3000 at high RPM provides worse cooling?

[ftmiranda]

Hello,

I got a ASUS Code X using a 8086 CPU and 32GB of G.Skill 3200 DDDR4 memory.
To cool down this I purchased the AIO EVGA CLC 280mm, replaced the fans from EVGA with Noctua IndustrialPPC3000, and I went even further by doing a push/pul configuration - a total of 4 Noctua fans (radiator sandwich) at the top of the case in exhaust mode. I got several other Noctua AF14s doing intake from front and bottom of the case.

The temperatures are fine, even with a 5.0Ghz overclock and using XMP profile for the memory. I noticed that when using the fans about 1500RPM, the temperature goes up !!! For example if I use 2800RPM of all 4 fans part of the AIO, the temperatures rise about 5C. If I keep the fans at 1000RPM to 1400RPM, I get a 5C decrease in temperatures.

I thought faster the fans and more ar gets through the radiator and out of it the better, but my tests are proving the opposite. Any ideas why?

[panzlock]

Could be various reasons.

a.) The air is moving so fast the friction and compression heats it up, resulting in hotter air passing over the radiator. This is why the Concorde stretched 6-10 inches at supersonic flight, due to the intense heating;

2.) Magic;

and

D.) the only viable explanation I can provide, is that the fans at higher RPM pump more air into the case than extracting fans can expel, thus trapping warm air inside and subsequently increasing component temperatures. How many intake fans vs. extraction fans do you have?

[ftmiranda]

panzlock wrote:
Could be various reasons.

a.) The air is moving so fast the friction and compression heats it up, resulting in hotter air passing over the radiator. This is why the Concorde stretched 6-10 inches at supersonic flight, due to the intense heating;

2.) Magic;

and

D.) the only viable explanation I can provide, is that the fans at higher RPM pump more air into the case than extracting fans can expel, thus trapping warm air inside and subsequently increasing component temperatures. How many intake fans vs. extraction fans do you have?

The Fans from the radiator (4 which 2 are pushing and 2 are pulling) are exhausting the air out of the case! all the other fans (AF14) are intake bringing cold air inside the case. The "phenomenon" happens only when I increase the RPM of the radiator fans ! Maybe option a) is the reason, maybe the fan is so good as pushes so much air through the radiator so fast that it does not cool down the radiator. So Noctua IndustrialPPC3000 is extremely overkill - I can probably replace them with a standard Noctua AF14 Chroma edition and run it at 1200RPM or lower and get the same results.

I will test that in a couple of weeks.

[Menthol]

What temps did you have with original fans? I am not familiar with the Noctua fans, are they designed for use on radiators? or as case fans

[ftmiranda]

Menthol wrote:
What temps did you have with original fans? I am not familiar with the Noctua fans, are they designed for use on radiators? or as case fans

Yes, they are designed as well for radiators: https://noctua.at/en/nf-a14-industrialppc-3000-pwm

The stock fans from EVGA would make a LOT of noise even running at a lower RPM - after a lot of research on forums, most people agreed that Noctua Industrial PPC3000 would be a great choice to get a lot of air pushed into the radiator.

To be honest the temps are basically the same thing using Noctua or EVGA fans, what changes is the noise level. Noctua running at 1300RPM are very silent. EVGA running at 1400RPM sounds like an airplane taking off.

[Menthol]

Ya fan noise can ruin the daily use of your PC, I have settled on Corsair Mag Lev fans myself, they run at less than 600rpm at idle and at full speed they create noise but it is the air being pushed not bearing noise.

I see in your specs "soon to be delidded" that will reduce temps substantially and allow even lower fan speed which in my opinion is much better than squeezing another 100mhz out of the CPU.

Once you hit 5.0Ghz on a system used daily there really is no benefit of higher mhz for higher noise level, finding the sweet spot for your use is what it is all about

[ftmiranda]

Hello there,

So finally my PC build is optimized:

The 8086k was delidded, and before running at 5Ghz temperatures were around 77C when running OCCT - after delidding and running at 5.2Ghz now it runs at 66C. The benchmark test ran for 45minutes, I believe that after all that time the AIO (EVGA 280mm + 2 Noctua Chroma 140mm fans).
I replaced all Noctua PPC3000 fans for the Noctua Chroma 140mm - the noise levels decreased from 46db to 39db.

What I'm concerned and I might ask on other threads is about the voltage on the Vcore - mine is at 1.34V and my system is running at 5.2Ghz and it looks like its stable - so far no blue screens or freezes (after hours and hours of gaming and benchmarks).
Everywhere I look says it needs 1.4V - I have seem other overclocker youtubers using 1.396V as well. Anyway - I think that I'm not sure I understand the relation to the vCore voltage and the multiplier when configuring the BIOS. My multiplier is 52 and my Vcore set to manual at 1.34V however during the OCCT test I can see the voltage gets pushed to 1.36V on the Vcore.

My setup as described is a Asus Maximus Code X and my CPU is a 8086k delidded.

[Guitarmageddon1]

ftmiranda wrote:
Hello there,

So finally my PC build is optimized:

The 8086k was delidded, and before running at 5Ghz temperatures were around 77C when running OCCT - after delidding and running at 5.2Ghz now it runs at 66C. The benchmark test ran for 45minutes, I believe that after all that time the AIO (EVGA 280mm + 2 Noctua Chroma 140mm fans).
I replaced all Noctua PPC3000 fans for the Noctua Chroma 140mm - the noise levels decreased from 46db to 39db.

What I'm concerned and I might ask on other threads is about the voltage on the Vcore - mine is at 1.34V and my system is running at 5.2Ghz and it looks like its stable - so far no blue screens or freezes (after hours and hours of gaming and benchmarks).
Everywhere I look says it needs 1.4V - I have seem other overclocker youtubers using 1.396V as well. Anyway - I think that I'm not sure I understand the relation to the vCore voltage and the multiplier when configuring the BIOS. My multiplier is 52 and my Vcore set to manual at 1.34V however during the OCCT test I can see the voltage gets pushed to 1.36V on the Vcore.

My setup as described is a Asus Maximus Code X and my CPU is a 8086k delidded.

in terms of reaching a particular multiplier, there is no hard-and-fast rule that you must use some certain voltage. There are rules for voltages in general that you do not want to go over (in terms of health and longevity of your chip) but when it comes to reaching a particular speed AKA multiplier, you go with the lowest that you can get away with because that's all that you need for stability. If that's what you need, then that is just it. That is a touch higher than what I use on my 8700 k for 5.1 / 4.9 AVX. I come to about 1.32 underload and 1.34 in BIOS. What is your load line calibration setting? it's always a balancing act for the performance that you absolutely must extract to be satisfied for your goal versus temperature and voltages to keep your chip alive for a long time. You may notice one or two hundred megahertz on benchmarks but never in real world applications

I would suggest a variety of tests at longer duration, but that's me. you can ask five different people and you will get five different criteria for what they consider stable

[Korth]

https://noctua.at/en/nf-a14-industrialppc-3000-pwm/specification

Forcing more air across the rads doesn't automatically mean lower temps, it makes more noise but there's diminishing returns on how much more heat can be lifted away.

If you've got a positive-pressure system then the heat generated by the fans themselves becomes part of the thermal load. Even if you've got a negative-pressure system you could still have dead-air or recycling-air spaces which lock heat in place. 7W per fan adds up fast and weighs against total system temps if it can't escape.

Fans can actually work against each other in a push-pull setup when they're spinning at mismatched rpms, this effect is multiplied with higher-powered fans like these.

I'd try repositioning fans for more chassis intake, get more forced airflow across and through the system to ensure the rad exhaust fans aren't pushing vacuum.