Question CPU drastically changes frequencies even when in idle

Jul 15, 2022
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I really don't know what happened, but my CPU uses maximum frequency for every single process. i monitored my CPU in idle and it fluctuates only between 3601 MHz and 4326 MHz, therefore the temperature drastically changes between 40C and 70C. I haven't noticed any program that uses the CPU in the background, it just boosts up like that when I open anything (Chrome, Steam, even volume mixer). I checked the BIOS to see if somehow the CPU magically overclocked itself, but it didn't. I verified the integrity of every file and everything seems fine. There are no viruses or malware either. This started happening only a few days ago. Any solutions?

Ryzen 7 3700X
RTX 2070
B550 Tomohawk
32 GB 3200 Ram
2TB SSD
750w power source
 
That's normal Ryzen boost behaviour. It boosts individual cores high...even to max clocks...for short bursts to finish a transitory processing task and then return it to an ultra low-power state. AMD called it a 'rush to idle' when the Zen 2 was released, which apparently results in lower over-all power useage than running multiple cores at a mid-range clock constantly.

But along with that, Windows is rarely truely "idle". There are hundreds of active processes, check Task Manager and you'll see them all. The vast majority are active-but-idle at any time but many wake up and demand some action of the CPU...things like search indexing, checking for updates, virus scan checks, and many more. When one wakes the CPU will boost a few cores in a round-robbin kind of affair until it's all gone..then idle...then another one wakes up and all over again.
 
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Jul 15, 2022
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That's normal Ryzen boost behaviour. It boosts high...even to max clocks...for short bursts to finish a transitory processing task and return to idle. AMD called it a 'rush to idle' when the Zen 2 was released.

But along with that, Windows is rarely truely "idle". There are hundreds of active processes, check Task Manager and you'll see them all. The vast majority are active-but-idle at any time but many wake up and demand some action of the CPU...things like search indexing, checking for updates, virus scan checks, and many more. When one wakes the CPU will boost a few cores in a round-robbin kind of affair until it's all gone..then idle...then another one wakes up and all over again.
Normal ryzen behaviour as it is, it's weird these temperature spikes started happening only recently. Previously it wasn't necessary for the CPU to jump to 70C to open a tab of chrome
 
Normal ryzen behaviour as it is, it's weird these temperature spikes started happening only recently. Previously it wasn't necessary for the CPU to jump to 70C to open a tab of chrome
It's also normal to also see a spike in temperature when a core boosts. It's really very minor since it's so short and only a tiny spot in one core since it also uses "hot spot" sensor reporting. You need to look at an average CPU temperature to get a good idea of what the true thermal load is. You can get that with HWInfo64.

What's hard to say is why it changed 'suddenly'...maybe something fixed itself in recent Windows update. Or then again, maybe something broke in a recent Chrome update that makes it hit the CPU a lot harder now.

Have you changed anything with your cooling...like moved the cooler around? or loosened the fasteners? Not that that would matter if it's just a spike when it's boosting as those are typically impossible to simply 'cool off'. It would affect the average CPU temperatures or case temps (if you motherboard reports them) though.

Added: one thing to do is run a heavy processing load to see cooling is adequate and it's trending OK for temperatures. A good one is Cinebench, run it for 20 minutes or so. What you'll see depends on what cooling you use and whether you've enabled PBO but anything below mid-80's is good. Low 90's should be about the max to accept but if it's in a hot summer-time room it might hit as high as 95C, it's Tjmax.
 
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Jul 15, 2022
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It's also normal to also see a spike in temperature when a core boosts. It's really very minor since it's so short and only a tiny spot in one core since it also uses "hot spot" sensor reporting. You need to look at an average CPU temperature to get a good idea of what the true thermal load is. You can get that with HWInfo64.

What's hard to say is why it changed 'suddenly'...maybe something fixed itself in recent Windows update. Or then again, maybe something broke in a recent Chrome update that makes it hit the CPU a lot harder now.

Have you changed anything with your cooling...like moved the cooler around? or loosened the fasteners? Not that that would matter if it's just a spike when it's boosting as those are typically impossible to simply 'cool off'. It would affect the average CPU temperatures or case temps (if you motherboard reports them) though.

Added: one thing to do is run a heavy processing load to see if it's trending OK for temperatures. A good one is Cinebench, run it for 20 minutes or so. What you'll see depends on what cooling you use and whether you've enabled PBO.
I haven't touched the cooler, although i'm thinking of opening up my pc and cleaning the dust off everything. Imma try that Cinebench as well. What's PBO?
 
I haven't touched the cooler, although i'm thinking of opening up my pc and cleaning the dust off everything. Imma try that Cinebench as well. What's PBO?
Dusting it can definitely help with heavy loads if the cooler fins are dust choked. Also make sure chassis fans are working to deliver cool air to the CPU so it's not drawing on the hot GPU exhaust air.

PBO is a sort of over-clocking, although not really. What it does is tell the boost algorithm to extend or ignore certain pre-set boost parameters (VRM current and power draw) so it boosts higher and longer. It helps it take advantage of significantly improved cooling, such as AIO liquid cooling. It still uses the same temperature limits to regulate boosting though so the effect is pretty tepid if using stock cooling.

One other thing to consider is that over the last few weeks the northern hemisphere has descended into what we call the dog-days of summer (when only mad dogs and the English stay out in the noon day sun, as Rudyard Kipling put it) with many regions experiencing very high temperatures. If you're affected by that your room ambient temperature may be 5 degrees or more higher than previously. That affects cooling quite a bit.
 
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Jul 15, 2022
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Dusting it can definitely help with heavy loads if the cooler fins are dust choked. Also make sure chassis fans are working to deliver cool air to the CPU so it's not drawing on the hot GPU exhaust air.

PBO is a sort of over-clocking, although not really. What it does is tell the boost algorithm to extend or ignore certain pre-set boost parameters (VRM current and power draw) so it boosts higher and longer. It helps it take advantage of significantly improved cooling, such as AIO liquid cooling. It still uses the same temperature limits to regulate boosting though so the effect is pretty tepid if using stock cooling.

One other thing to consider is that over the last few weeks the northern hemisphere has descended into what we call the dog-days of summer (when only mad dogs and the English stay out in the noon day sun, as Rudyard Kipling put it) with many regions experiencing very high temperatures. If you're affected by that your room ambient temperature may be 5 degrees or more higher than previously. That affects cooling quite a bit.
So I used Cinebench and i never really got past 76C on multi-core benchmark (11657 pts) and past 66C on single-core benchmark (1247 pts). I guess everything is ok with the cooling, especially since i have an air cooler, but it pains me to see the temp at 70 on idle. Even on Cyberpunk 2077 it doesn't go beyond 76C.

I live at the countryside, so it's quite cold compared to city temperatures, so my PC should be ok I guess. Imma still clean the dust.
 

JeffreyP55

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Mar 3, 2015
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I really don't know what happened, but my CPU uses maximum frequency for every single process. i monitored my CPU in idle and it fluctuates only between 3601 MHz and 4326 MHz, therefore the temperature drastically changes between 40C and 70C. I haven't noticed any program that uses the CPU in the background, it just boosts up like that when I open anything (Chrome, Steam, even volume mixer). I checked the BIOS to see if somehow the CPU magically overclocked itself, but it didn't. I verified the integrity of every file and everything seems fine. There are no viruses or malware either. This started happening only a few days ago. Any solutions?

Ryzen 7 3700X
RTX 2070
B550 Tomohawk
32 GB 3200 Ram
2TB SSD
750w power source
If you set all tweak functions to auto, that is normal. The CPU uses what it needs. I enable DOCP and that's it. AMD 5950x.
 
Jul 15, 2022
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If you set all tweak functions to auto, that is normal. The CPU uses what it needs. I enable DOCP and that's it. AMD 5950x.
I see. It's wierding me out though since it only started happening a few days ago without me interfering with any settings. Before this, it would just stay at 45C on idle and I could open Chrome or any other not-very-demanding software without having the CPU skyrocket to 4300MHz and 70C
 

JeffreyP55

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Mar 3, 2015
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I see. It's wierding me out though since it only started happening a few days ago without me interfering with any settings. Before this, it would just stay at 45C on idle and I could open Chrome or any other not-very-demanding software without having the CPU skyrocket to 4300MHz and 70C
You can set clock frequency settings. I like the not having a fixed frequency. Idle goes way down. If I process a photo or video it gets really spunky. :) Depends what you are going to use the CPU for.
Maybe your BIOS was reset somehow. That would do it.
 
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