• Guest, The rules for the P & N subforum have been updated to prohibit "ad hominem" or personal attacks against other posters. See the full details in the post "Politics and News Rules & Guidelines."

Question cpu running hot during idle

merk

Senior member
May 29, 2003
454
7
91
Hey all,

I have an intel i9 7940x - default settings, i never bother with overclocking. I have a corsair hydro H100i v2 liquid cooler on it. I think i installed it about 4 years ago. I'm pretty sure when i first installed it it was pretty quiet. but now it's pretty much a vacuum cleaner all the time.

When i open corsair link it shows the cpu sitting at around 80c while idle and the fans on the cooler are pretty much running at full - 2600rpm.

I'm assuming whatever thermal past I have on the cpu has dried out and it needs to be cleaned and re-applied. I ordered some high end thermal paste (thermal grizzly conductonaut). But just thought I'd post on here in case there could be something else I might have missed that's causing the higher temps and loud fans.
 

Furious_Styles

Senior member
Jan 17, 2019
409
139
86
I think it's more likely the pump has failed, or your liquid cooler has lost most of its water. But always try simple stuff first - change the paste and clean the radiator.
Agreed, much more likely the pump has failed than the thermal compound has dried up. I've refurbished mobos where I've had to scrape it off with a knife and it still was doing a decent job transferring heat.
 

DrMrLordX

Lifer
Apr 27, 2000
18,206
7,100
136
Shouldn't Corsair Link report the pump failure? Doesn't it have pump controls along with fan controls?
 

merk

Senior member
May 29, 2003
454
7
91
according to their software the pump is still going. However, blowing the dust off the radiator seems to have helped some. Fans speeds are pretty low right now with the cpu temp at 70c. Still higher then it should be at idle but at least it's a little quieter. And if i switch the pump from quiet to performance, the cpu is down to around 53c. Which i think is still hotter than it should be. But definitely a lot better.

I think i'll still try replacing the thermal paste though since i bought it.
 

DrMrLordX

Lifer
Apr 27, 2000
18,206
7,100
136
You can usually tell if the pump is running from vibration/noise. They aren't silent.

edit: it may be that your pump is still working but is beginning to fail? It's hard to say. I won't disagree with the others when they assume that the pump is the weak link in an AiO (it is), but if it's just completely shut down, Corsair Link will tell you.
 

merk

Senior member
May 29, 2003
454
7
91
You can usually tell if the pump is running from vibration/noise. They aren't silent.
i bumped the pump up to max and couldnt hear a difference from outside the case, but it did make a difference in temps so the pump must still be working. their software says its running between 2000 and 3100rpm depending on which setting i use
 

DrMrLordX

Lifer
Apr 27, 2000
18,206
7,100
136
i bumped the pump up to max and couldnt heard a difference from outside the case, but it did make a difference in temps so the pump must still be working. their software says its running between 2000 and 3100rpm depending on which setting i use
Okay, just be advised that running it harder will shorten whatever life it has left. What's the warranty on that unit?
 

merk

Senior member
May 29, 2003
454
7
91
Okay, just be advised that running it harder will shorten whatever life it has left. What's the warranty on that unit?
I'm sure the warranty is already gone, it's about 4 years old. I'm just going to leave it at the max setting for a few days until i get the new thermal paste, then hopefully reapplying that I can run the pump at a lower setting. I'd be much more concerned about shortening the life of the cpu then the cpu cooler given the price ;)
 

UsandThem

Elite Member
Super Moderator
May 4, 2000
15,138
5,941
146
Those AIO coolers don't really go past 4-5 years before the really coolant begins degrading. Some models you can replace it with new, but for the most part the entry-level AIO coolers are made to be replaced after so many years.

If your new thermal paste doesn't significantly drop the temps (after only four years, I'd guess it's not the paste), I'd look into replacing the coolant mixture (if possible with that particular model).
 

merk

Senior member
May 29, 2003
454
7
91
Those AIO coolers don't really go past 4-5 years before the really coolant begins degrading. Some models you can replace it with new, but for the most part the entry-level AIO coolers are made to be replaced after so many years.

If your new thermal paste doesn't significantly drop the temps (after only four years, I'd guess it's not the paste), I'd look into replacing the coolant mixture (if possible with that particular model).
According to what I just read online, this cooler should never need it's coolant replaced. And I was also wrong about the warranty - it's a 5 year warranty. So...i'll swap out the thermal paste once i get it and if i still get high temps, I'll see if i can get the unit replaced.
 

merk

Senior member
May 29, 2003
454
7
91
So i just cleaned off the old thermal paste. I dont think there was anything wrong with it as it was still tacky and malleable i.e. it didnt dry out. Although it looks like i might have applied a little more then needed. But if that were the issue it would have been a problem since day 1.

Anyhow, i applied the new paste, and that shaved off a few degrees at idle - now it's hovering at a little bit below 50c at idle.

That still seems high - from what I've read, i should be seeing something around 35c at idle with this cooler. Does 35c seem reasonable with this cpu and this cooler?
 

merk

Senior member
May 29, 2003
454
7
91
Using windows 10? Is the CPU showing low usage when at idle? Because some are having issues https://www.extremetech.com/computing/322523-if-youre-having-problems-with-high-cpu-usage-in-windows-10-grab-this-update
Right now just typing this reply with nothing running besides background stuff, cpu load is bouncing between 1-3%. Core temps are anywhere from just under 50c to 57c. cpu package temp is 56c. Thats with the cooler pump at max and cooler fan at 1500rpm and cooler temp at 45c
 
  • Like
Reactions: DAPUNISHER

ASK THE COMMUNITY