My CPU is Slowing Down

[KatetheSuperfish]

Hi, I am new to this forum.

 

I built my PC earlier this year. The specs are down below. I have done a moderate overclockon the CPU to 4.2 GHz. The GPU is also slightly overclocked & have enabled XMP. However occasionally I notice that my PC runs slower than usual & discovered that the CPU is running at around 800 MHz & it stays that way for some period of time. The next time I power up though it is running fine again at 4.2 GHz. Very frustrating.

 

Has anyone else experienced this problem? Can someone please assist? Thanks very much.

 

CPU: Intel Core i7-5820K

MOBO: Asus X99 E-WS

RAM: 16 Gb at 2400 MHz

GPU: Asus GTX 980 (Reference card)

Windows 10

 

 

Kate

[Oberon.Smite]

Check your temps. Might be thermal throttling, always a good idea to check.

[manikyath]

if an intel cpu is idle (doesnt have any work) it'll clock down to 800MHz (not sure where amd clocks to.)

also, whats temps like?

[Laputacake]

Probably thermal throtting. Whats the cooler?

[techguru]

if an intel cpu is idle (doesnt have any work) it'll clock down to 800MHz (not sure where amd clocks to.)

also, whats temps like?

this

[KatetheSuperfish]

I am using an Antec 120mm liquid cooler (with push pull fans). Temps are averaging 45 - 50 deg Celsius when idle. It hovers around 68 - 72 deg Celsius under load. That's not too hot is it? Thanks

 

Kate

[Deagon]

if an intel cpu is idle (doesnt have any work) it'll clock down to 800MHz (not sure where amd clocks to.)

also, whats temps like?

This is exactly what is happening. You are fine this is normal. When you put it under load it should shoot up. If it was always running at max speed it'd die pretty fast.

 

 68 - 72 deg Celsius under load. That's not too hot is it? Thanks

 

Kate

Yes, that is WAY too hot. like I can't believe it isn't shutting off at those temps. My CPU under max load (and its an older high heat output CPU) runs at about 32-37 Celsius. I'd be down right scared if my CPU was running at 72 c, that's like 161 F, which is crazy hot!

[KatetheSuperfish]

So the cpu is powering itself down, because of the heat. I have had a couple of unexpected restarts since I OCed it. I just thought that the liquid cooler could handle it. And I also thought thst 4.2 GHz at 1.35 core voltage is a moderate and conservstive OC. I kinda remember that it was just reaching 70 deg C during my post-overclock stress tests. Should I bring the CPU down to maybe 4.0 GHz or 3.9 GHz and lower the core voltage as well? Would that bring down my temps so that the CPU doesn't throttle down anymore?

[Deagon]

So the cpu is powering itself down, because of the heat. I have had a couple of unexpected restarts since I OCed it. I just thought that the liquid cooler could handle it. And I also thought thst 4.2 GHz at 1.35 core voltage is a moderate and conservstive OC. I kinda remember that it was just reaching 70 deg C during my post-overclock stress tests. Should I bring the CPU down to maybe 4.0 GHz or 3.9 GHz and lower the core voltage as well? Would that bring down my temps so that the CPU doesn't throttle down anymore?

When under high load and then slows down, yes it is heat throttling. When it sits around and drops to 800, it is just idle throttling. 

 

The liquid cooler *SHOULD* be able to handle it, but its depends on ambient temperatures really.

 

I personally won't give you advice about your particular overclock because i haven't worked much with your particular CPU wouldn't want to give you damaging or incorrect advice about how you should handle that. But as a general rule less speed = less heat

[techguru]

So the cpu is powering itself down, because of the heat. I have had a couple of unexpected restarts since I OCed it. I just thought that the liquid cooler could handle it. And I also thought thst 4.2 GHz at 1.35 core voltage is a moderate and conservstive OC. I kinda remember that it was just reaching 70 deg C during my post-overclock stress tests. Should I bring the CPU down to maybe 4.0 GHz or 3.9 GHz and lower the core voltage as well? Would that bring down my temps so that the CPU doesn't throttle down anymore?

72c isn't terrible..but its not good

I would reapply the thermal paste (properly)..and tighten down the cooler a bit more

[KatetheSuperfish]

When under high load and then slows down, yes it is heat throttling. When it sits around and drops to 800, it is just idle throttling. 

 

The liquid cooler *SHOULD* be able to handle it, but its depends on ambient temperatures really.

 

I personally won't give you advice about your particular overclock because i haven't worked much with your particular CPU wouldn't want to give you damaging or incorrect advice about how you should handle that. But as a general rule less speed = less heat

 

 

72c isn't terrible..but its not good

I would reapply the thermal paste (properly)..and tighten down the cooler a bit more

I took your advice, Techguru as well as Deagon's. Thanks so much.

 

The cpu cooling block was unfastened, cleaned the the thermal paste off, reapplied thermal paste (a little less this time) and re-installed the cooling block making sure it was nice and tight against the cpu. I replaced one of the 120mm fans attached to the radiator, that was making a whirring noise and seemed to be spinning a little unevenly and slower than the fan next to it. Also moved the PC into another room on the "cooler" side of the house.

 

Ok, on idle the temps are now 30° - 33°C. Then I rendered a 20 min HD video and the temps were 45° to 50°C. I'm doing a Prime95 blend test at the moment and temps are hovering around 53°C.

 

The CPU has also maintained 4.2 GHz so far.

 

Thanks to you both and all the others who have posted. I'll keep the stress test going for another hour or two and post the results in the morning.  

[Vivilacqua1]

This is exactly what is happening. You are fine this is normal. When you put it under load it should shoot up. If it was always running at max speed it'd die pretty fast.

 

Yes, that is WAY too hot. like I can't believe it isn't shutting off at those temps. My CPU under max load (and its an older high heat output CPU) runs at about 32-37 Celsius. I'd be down right scared if my CPU was running at 72 c, that's like 161 F, which is crazy hot!

That's fine. Intel chips are safe up to around 88c

[Deagon]

I took your advice, Techguru as well as Deagon's. Thanks so much.

 

The cpu cooling block was unfastened, cleaned the the thermal paste off, reapplied thermal paste (a little less this time) and re-installed the cooling block making sure it was nice and tight against the cpu. I replaced one of the 120mm fans attached to the radiator, that was making a whirring noise and seemed to be spinning a little unevenly and slower than the fan next to it. Also moved the PC into another room on the "cooler" side of the house.

 

Ok, on idle the temps are now 30° - 33°C. Then I rendered a 20 min HD video and the temps were 45° to 50°C. I'm doing a Prime95 blend test at the moment and temps are hovering around 53°C.

 

The CPU has also maintained 4.2 GHz so far.

 

Thanks to you both and all the others who have posted. I'll keep the stress test going for another hour or two and post the results in the morning.  

That is much better! glad to be of some help.

 

 

That's fine. Intel chips are safe up to around 88c

Yes, but that isn't the point, it shouldn't be running that hot, especially with a liquid cooler, seems she got it all figured out though.

[KatetheSuperfish]

That's fine. Intel chips are safe up to around 88c

 

 

That is much better! glad to be of some help.

 

 

Yes, but that isn't the point, it shouldn't be running that hot, especially with a liquid cooler, seems she got it all figured out though.

 

Temps are much better than before. One core (or thread?) got to 57°C in the Prime95 blend test and the reached a max of 54°C after running this stress test for two and a half hours.

As I as I can see it also has not slowed itself below my overclocked 4.2 GHz since the fix.

Thanks all for your help & input.