3900X Temps - 95C in Prime95

Epos7

Gawd
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Aug 31, 2015
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Running Prime95 for 5-10 minutes, my CPU hits the 95C limit and slowly throttles down to ~3.5Ghz.

Just curious about what sort of results others are getting as there's some mixed information out there regarding if this is normal behavior.

I'm using the Gigabyte X570 ITX board and a Noctua C14 cooler.
 

capt_cope

Gawd
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Apr 12, 2009
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947
Not really apples to apples since I'm running a custom loop (420 + 280) but when I run Prime95 (small FFT) it'll jump to ~75 right away and then slowly creep up and stabilize around 79-80 after half an hour or so and the clocks hover at ~3.9Ghz
 

SmokeRngs

[H]ard|DCer of the Month - April 2008
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Pretty typical for a prime 95 stress test

Especially if it's using AVX.

You may want to check the thermal goop application and the heatsink mating to make sure everything is making proper contact as well.
 

Epos7

Gawd
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Thanks all. I did check the thermal goop and I've got good coverage there. I didn't tighten the bolts on my C14 down all the way as I didn't want to overdo it, so I could see if screwing those down further provides better thermal conductivity.

Overall I'm not too worried about it as I'm seeing normal scores in benchmarks like Cenebench R20, where it hits about 74C during the first run.
 

SmokeRngs

[H]ard|DCer of the Month - April 2008
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Thanks all. I did check the thermal goop and I've got good coverage there. I didn't tighten the bolts on my C14 down all the way as I didn't want to overdo it, so I could see if screwing those down further provides better thermal conductivity.

Overall I'm not too worried about it as I'm seeing normal scores in benchmarks like Cenebench R20, where it hits about 74C during the first run.

Check the settings for Prime95. There should be an option to turn off AVX; try that and see how the temps are. AVX loads roast CPUs and Prime95 is no different.
 

clockdogg

[H]ard|Gawd
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Thanks all. I did check the thermal goop and I've got good coverage there. I didn't tighten the bolts on my C14 down all the way as I didn't want to overdo it, so I could see if screwing those down further provides better thermal conductivity.

Overall I'm not too worried about it as I'm seeing normal scores in benchmarks like Cenebench R20, where it hits about 74C during the first run.

By design, Noctua mounts can't be over-tightened. You can screw without fear.
 

IdiotInCharge

NVIDIA SHILL
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14,679
Yea, not surprised. Prime will test yer cooling and take it to its maximum.

Adding to that- I wouldn't be worried about Prime 95 heating up the CPU, nor the CPU throttling down.

That's the CPU working as designed.

If Prime 95 crashed, or worse, other things crash, then there's room to worry.

If you want cooler temperatures, you just have to figure out how to get more heat away from the CPU and into the room with you ;).
 

Epos7

Gawd
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I tried a few things - turning off AVX and AVX2; tightening the cooler down all the way; removing my intake filter. Still hitting the 95C cap after 5-6 minutes.

Sounds like it's normal behavior so I'm not worried about it. I don't expect it to be an issue in normal use, just was curious if others were seeing similar temps.

In the future I may try reversing the direction of some of my fans. Currently have the C14 140mm fans as intake with a 92mm exhaust fan on the back of the case. I've also got a 120mm intake fan next to the C14.
 

thesmokingman

Supreme [H]ardness
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I tried a few things - turning off AVX and AVX2; tightening the cooler down all the way; removing my intake filter. Still hitting the 95C cap after 5-6 minutes.

Sounds like it's normal behavior so I'm not worried about it. I don't expect it to be an issue in normal use, just was curious if others were seeing similar temps.

In the future I may try reversing the direction of some of my fans. Currently have the C14 140mm fans as intake with a 92mm exhaust fan on the back of the case. I've also got a 120mm intake fan next to the C14.

Why?? Do you expect your cooler to do better?
 

pendragon1

Extremely [H]
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your cooler is barely enough as its just a sideways single tower and you have it in an itx case right? so this is would be normal.
 

knox1711

Weaksauce
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Apr 4, 2006
Messages
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I got the same max'd heat result with Prime 95, and did some reading. Apparently it is to be expected. I have a d-15 and it hit 95 deg repeatedly at the 5 minute mark as apparently it cycles through different tests (I think it is the FFT that is the culprit, but may be wrong there)...
 

Zepher

[H]ipster Replacement
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I ran Prime95 for 90 minutes last night on a 3900X at stock settings and it was running at 58-62*C with an H100i cooler

The image below was after 30 minutes. I forgot about it and when I was about to shut down Prime95 an hour later it was sitting at 58*C for the few minutes I was watching it before shutting it down.
h100i-prime95.jpg

Radiator won't fit in this case,

253658_IMG_3899.jpg
 
Last edited:

Epos7

Gawd
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Aug 31, 2015
Messages
856
I got the same max'd heat result with Prime 95, and did some reading. Apparently it is to be expected. I have a d-15 and it hit 95 deg repeatedly at the 5 minute mark as apparently it cycles through different tests (I think it is the FFT that is the culprit, but may be wrong there)...

Thanks. Sounds exactly like what I was seeing.
 

OC-FTW

n00b
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Nov 1, 2019
Messages
4
3900X's spec sheet lists 95C as the maximum temperature, so what you are seeing is expected. The worst case scenario is the CPU asserting PROCHOT and the CPU will throttle to really low frequency (in the <=MHz range) to prevent permanent damage to your CPU. If you are not overclocking, then I hope it is not hitting 95C...
 

knox1711

Weaksauce
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Apr 4, 2006
Messages
67
Thanks. Sounds exactly like what I was seeing.

FYI, I switched from the NH-D15 air cooler to an ARCTIC Liquid Freezer II 280 and my temps dropped by 10-20 C across the board for all uses. On Prime 95, where I hit 95 C at the 5 min mark, the AIO cooler held temps in the 75-78 C range. So basically 20 C cooler, pretty amazing, since the Arctic is about $5 cheaper than the Noctua...lolz
 

Epos7

Gawd
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Aug 31, 2015
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856
FYI, I switched from the NH-D15 air cooler to an ARCTIC Liquid Freezer II 280 and my temps dropped by 10-20 C across the board for all uses. On Prime 95, where I hit 95 C at the 5 min mark, the AIO cooler held temps in the 75-78 C range. So basically 20 C cooler, pretty amazing, since the Arctic is about $5 cheaper than the Noctua...lolz

Always been a fan of air cooling, but perhaps this is a sign I need to look into an AIO.
 

Jamie Marsala

Limp Gawd
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Mar 9, 2016
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316
FYI, I switched from the NH-D15 air cooler to an ARCTIC Liquid Freezer II 280 and my temps dropped by 10-20 C across the board for all uses. On Prime 95, where I hit 95 C at the 5 min mark, the AIO cooler held temps in the 75-78 C range. So basically 20 C cooler, pretty amazing, since the Arctic is about $5 cheaper than the Noctua...lolz

I saw about the same. Sure I can creep up into the 90's after like 30 minutes but for the most part now it stays below 90 and even in the 70-80 range.
 
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