Question My CPU is almost at 100C on idle and my fans are blowing out cold air

CorruptBanana

Junior Member
May 13, 2022
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I've had my computer since 2015 and I had this issue a couple months back but it was because of no thermal paste, this issue started happening today, I realligned my cooler and checked the thermal paste and it's all still there and has rubbed on to the cpu as well so it's been touching the cpu.

I tried checking my BIOS to see if my fans were working properly and they're both at max rpm (1800 on cpu fan and 1300 on the system fan) I have a i7 4790k 4gh 4 cores and it's hooked up to a MSI Z97 Gaming 3 motherboard. The cooler is the same one that came with the cpu, maybe it needs replaced with a better fan?
 

igor_kavinski

Diamond Member
Jul 27, 2020
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The contact between the heatsink base and the CPU IHS is not good. Try tightening the screws so the heatsink base presses down a bit more on the CPU IHS.
 

VirtualLarry

No Lifer
Aug 25, 2001
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Intel stock fan? Many years / hairballs later? Could've cracked a (plastic) mounting leg, too.

Just replace it with a Tower heatpipe heatsink.
 
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Tech Junky

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Jan 27, 2022
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Sounds more like the sensor / application monitoring the temp isn't working any longer.

If it's blowing cool air and running fine then it's just the sensor is shot and monitoring won't work.
 
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DAPUNISHER

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Pop the CMOS battery out for a minute with the system unplugged. If the problem remains, and given how old the system is, the best solution is to replace the cooler as Larry suggested. $30 or less ensures it is not a cooler issue. At which point, if the erroneous temps persist, you can ignore them.

Be aware that restoring defaults by clearing CMOS may require re-enabling XMP for your memory.
 

Hitman928

Diamond Member
Apr 15, 2012
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Sounds more like the sensor / application monitoring the temp isn't working any longer.

If it's blowing cool air and running fine then it's just the sensor is shot and monitoring won't work.
Blowing cool air can be an indication that something is wrong with the heatsink contact as the heat from the CPU isn't being transferred to the heatsink to be blown off by the fan.
 
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Tech Junky

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@Hitman928
And you quoted the part mentioning if it's running fine / cool air it's the sensor.

If it were overheating it wouldn't be running well or shutdown due to thermals. My laptop blows ambient air temps when not under stress. Now, if it's under stress it should generate some heat from the exhaust. Hence if the CPU is reporting 100C and running fine / no heat it's not an issue. If it's struggling to do things then there's probably a physical issue with either the HS or the paste not making proper contact.

When playing around with testing different pastes I did run into an instance of one paste lasting 3-4 days and then going to hell on me shooting temps to the max but, the heat output from the exhaust was there. I swapped the paste for a graphite pad instead and it took care of the issue and allowed for moving the HS in the laptop w/o having to deal with cleaning everything to repaste after. On the laptop it's preferable when you go digging around inside the chassis or decide to pull the HS to clean the fins / fans of any potential debris.

I use the Graphite now on all systems just for simplicity sake and have decent temps on all devices. Sure, it's not like using LM and seeing huge temp variances but, it's substantial enough to keep things from throttling too bad.
 
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Hitman928

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@Hitman928
And you quoted the part mentioning if it's running fine / cool air it's the sensor.

If it were overheating it wouldn't be running well or shutdown due to thermals. My laptop blows ambient air temps when not under stress. Now, if it's under stress it should generate some heat from the exhaust. Hence if the CPU is reporting 100C and running fine / no heat it's not an issue. If it's struggling to do things then there's probably a physical issue with either the HS or the paste not making proper contact.

When playing around with testing different pastes I did run into an instance of one paste lasting 3-4 days and then going to hell on me shooting temps to the max but, the heat output from the exhaust was there. I swapped the paste for a graphite pad instead and it took care of the issue and allowed for moving the HS in the laptop w/o having to deal with cleaning everything to repaste after. On the laptop it's preferable when you go digging around inside the chassis or decide to pull the HS to clean the fins / fans of any potential debris.

I use the Graphite now on all systems just for simplicity sake and have decent temps on all devices. Sure, it's not like using LM and seeing huge temp variances but, it's substantial enough to keep things from throttling too bad.
I guess I didn't assume the OPs machine was running well as he doesn't say that it is (or isn't tbf).
 

DAPUNISHER

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@Hitman928


I use the Graphite now on all systems just for simplicity sake
If you mean the pads? Then right on. I test/mess with, a lot of CPUs and boards. Since getting turned on to them by Phil'scomputerlab, they have taken the mess out of messing around with.
 

DAPUNISHER

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Another reason to use the pads with Ryzen. It would stop the reddit subs from constantly having pics of the CPU stuck to the cooler. ;)
 
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Hitman928

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Another reason to use the pads with Ryzen. It would stop the reddit subs from constantly having pics of the CPU stuck to the cooler. ;)
I never understood this. TIM paste can be pretty sticky with the large IHS on Ryzen CPUs, but it's really not that hard to get it off.

Edit: Also +1 on the pads. Modern pads work great as long as you aren't trying to push your CPU to the limit.
 
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DAPUNISHER

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I never understood this. TMI paste can be pretty sticky with the large IHS on Ryzen CPUs, but it's really not that hard to get it off.
I understand it, it's impatience and inexperience. I think Intel has a superior solution in that area. Too bad their stock mounting plastic pins are garbage. Even the locked models will boost higher with aftermarket. My 10100f hits 4.4GHz with an ancient model of the Hyper 212 evo. With the stock it never reached the claimed 4.3 boost, and was noisy.

But the pads work well, and are no muss no fuss. Perfect for those of use swapping CPUs often.
 
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Tech Junky

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Jan 27, 2022
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Wow.... I finally found some people that appreciate thinking outside of the box and use pads as well. When I've brought this up in the past it's usually a huff 'n puff about grizzlies and kryonauts being the bestest.

Paste is fine in some applications but, if you ever do work on your system desktop or laptop you know how much of a PITA is it to deal with. I had not heard of the ID10TS on reddit though.

I did spot something the other day about a new LM pads now being used in some laptops. Guess that make some of the issues with needing to dam up around it to prevent shorts from happening.

Figure graphite is good enough to not worry about killing my systems if LM were to spready and it doesn't dry out ever. They are a bit peculiar in how they delay ramp up / down of the fans.
 
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DAPUNISHER

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Wow.... I finally found some people that appreciate thinking outside of the box and use pads as well.
My POV is: A couple of degrees centigrade isn't going to negatively impact already excellent temps. Not having to clean off and reapply paste each time is more than worth it. And long term it is cheaper than all that paste I would go through.

Besides, I don't care if I am not seen as avant-garde or hardcore; because I'm not. ;) But I do know how to be frugal, efficient, and effective.
 

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