Kotetsu with washers cause high temps on i5-8400

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LH
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Kotetsu with washers cause high temps on i5-8400

Post by LH » Sun Jul 08, 2018 7:26 pm

I just installed a Scythe Kotetsu on an Intel Core i5-8400 in an Asus ROG Strix H360-I Gaming motherboard. I used the 1151 spacers and could still twist/rotate the Kotetsu even after fully-tightening the mounting screws. I am thinking about reinstalling the Kotetsu without the 1151 spacers, but I am kind of concerned about long-term damage caused by excessive pressure because I'm hoping this computer lasts a good five to ten years.

The i5-8400 idles at 29 C, which seems fine. However, the Prime95 29.4 small FFT torture test (with AVX) pushes the CPU temperature up very quickly. I stopped Prime95 after two minutes when it reached 88 C. If I run the Prime95 29.4 small FFT torture test (without AVX via CpuSupportsAVX=0), the load temperature stabilizes at 73 C after ten minutes.

Is 73 C an okay a load temperature for an i5-8400? That said, I built this new computer for my parents, who will use it only for surfing the web, so they're not going to hit 73 C. They don't really care about fan noise, but this new computer is already quieter (at idle) than their current computer...

P.S. After this build, I'm going back to Thermalright. I've always used Thermalright CPU coolers and was itching to try a True Spirit 140 Power, but it wouldn't fit in the Nano S.

[Mod: Moved post to it's own topic]

CA_Steve
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Re: Kotetsu with washers cause high temps on i5-8400

Post by CA_Steve » Mon Jul 09, 2018 6:48 am

Intel slightly reduced the thickness of their cpu package when Skylake came out. Some Scythe coolers had screws that were maybe a turn too long and there were a few reports of the CPU package being damaged if the PC was jostled a lot (like during shipping). So, Scythe added the washers. However, not all motherboards are the same thickness plus there may be some variability in the socket's mounting to the board.

If you can move the mounted cooler, then the washers are adding too much space. Remove the washers, don't shake your PC like a dice box and you'll be fine.

Abula
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Re: Kotetsu with washers cause high temps on i5-8400

Post by Abula » Mon Jul 09, 2018 7:28 am

I would probably check if the Kotetsu is doing good contact, just dissemble it and see how was your spread of paste, if its too thick or didn't spread well, the efficiency of the cooler diminishes. I usually always do a mount test, and from there i do adjustments on my real mount.

Now 73C is not a bad temperature at all, specially not knowing the conditions its at, what rpms are your case and cpu fans? maybe its a very restrictive case, some filters can lower the airflow in some cases you lose around 5C of internal temperature.... lots of factors.

Now Prime95 is a very unusual load that its very unlikely to ever be encounter by the average user, so i would assume even in high loads your parents will never hit above 70C, that said, if you truly want to lower the temps of the CPU, delid it or send it to a delider, you will lower around 10-20c on load, in my case i have two 8700K, one delided other isnt, about 14C difference on prime95, on normal browsing, watching videos, checking emails, etc, you wont see much gain, except it spikes a little higher on the none delided but the spikes lower very fast so its not a big gain.

CA_Steve
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Re: Kotetsu with washers cause high temps on i5-8400

Post by CA_Steve » Mon Jul 09, 2018 7:47 am

He can rotate the cooler :) Washer removal will solve the problem.

LH
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Re: Kotetsu with washers cause high temps on i5-8400

Post by LH » Mon Jul 09, 2018 9:27 pm

Thanks for the feedback!

I re-mounted the Kotetsu without the 1151 spacers. I cleaned the Kotetsu and the CPU using Arctic Silver ArctiClean. Like before, I used Arctic Silver 5 and "tinted" both the Kotetsu and the CPU prior to adding a vertical line of thermal paste per Arctic Silver instructions. I tightened the mounting screws as much as I dared, and stopped when I could not rotate the Kotetsu anymore--well maybe a tiny tiny bit, but much less movement than before.

Immediately after, I ran the Prime95 29.4 small FF torture test (without AVX) for ten minutes and the load temperature stabilized at 65 C after ten minutes (both CPU fan and exhaust fan around 1100 RPM, intake fan around 700 RPM). I let it idle for a couple of hours and then ran another ten-minute torture test, which stabilized at 63 C and occasionally hit 64 C.

Idle temperature stayed the same around 29 C (in BIOS) and 27 C in Windows. CPU fan and intake fan around 600 RPM, exhaust fan around 850 RPM.

I used the "Standard" Q-Fan settings in the BIOS, except I enabled the AIO Pump connector and set it to Auto for use with the intake fan. I'll play with the fan settings for less noise at idle--just so I don't get annoyed by the fan noise when my parents need help with something on their new computer... :mrgreen:

I had a typo earlier with my motherboard name. Here are the specs of this computer:

Intel Core i5-8400 Processor
Asus ROG Strix H370-I Gaming motherboard with plastic I/O cover removed (it was covering the top of the VRM heatsink)
Scythe Kotetsu SCKTT-1000 CPU heatsink with stock fan
Fractal Design Define Nano S computer case with stock 120mm rear fan and stock 140mm front fan
G.Skill Ripjaws V DDR4-2666 8GB memory
Intel SSD 760p NVMe M.2 256GB
Seasonic Focus 450 Gold power supply

Abula
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Re: Kotetsu with washers cause high temps on i5-8400

Post by Abula » Mon Jul 09, 2018 10:19 pm

LH wrote:Immediately after, I ran the Prime95 29.4 small FF torture test (without AVX) for ten minutes and the load temperature stabilized at 65 C after ten minutes (both CPU fan and exhaust fan around 1100 RPM, intake fan around 700 RPM). I let it idle for a couple of hours and then ran another ten-minute torture test, which stabilized at 63 C and occasionally hit 64 C.
So about 8C for dropping the washers? nice gain. Given that 65C is a great temperature, and not likely that any activity of your parents put that kind of load to the cpu, you could even lower the rpms fan curve more, in favor of more quiet operation, thats what most of us do here in terms of taking the heat for quieter operation, but its up to you, whatever you find acceptable in terms of temperature and noise.

CA_Steve
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Re: Kotetsu with washers cause high temps on i5-8400

Post by CA_Steve » Tue Jul 10, 2018 6:35 am

Glad it worked out. How do you like the Seasonic Focus Gold?

LH
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Re: Kotetsu with washers cause high temps on i5-8400

Post by LH » Wed Jul 11, 2018 5:54 am

I would have preferred a 400W or even a 350W PSU to run this computer at higher efficiency on the PSU, but that might also make its fan run at a higher RPM since the PSU would run at a "higher" load.

This computer just needs the hard-wired mains and CPU cables (no discrete graphics card or SATA drives), so the semi-modular cables eliminate cable clutter.

So far, I can't hear the PSU fan over the other fans and it doesn't seem to have the sporadic coil whine of my Seasonic 520W fanless, so overall, I like the Seasonic Focus 450W Gold.

After "optimizing" the fan speeds in Q-Fan, the exhaust fan dropped from 850 RPM down to around 550 RPM at idle. That made a big noise reduction when this computer is at idle. :mrgreen:

CA_Steve
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Re: Kotetsu with washers cause high temps on i5-8400

Post by CA_Steve » Wed Jul 11, 2018 7:10 am

nice.

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