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Daharen

Rapidly Fluctuating CPU Frequency

That's how CPUs work.

When they need to compute something the frequency boosts up.

Even at idle there are thousands of things happening in the background of a computer.

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Posted · Original PosterOP

So the way this question is normally asked I think incurs the 'wrong' sorts of answers. I want to phrase this very carefully:

Is it normal for people who use variable frequencies to NEVER have stable low frequencies when idle, that is low frequencies are AT BEST only momentary while the CPU frequency rapidly swings between the lowest frequency and high frequencies... OR is there a way to make the processor stop rapidly fluctuating and maintain 'low' frequencies in idle unless it REALLY needs to use all cores or significantly overclock for the current processes? 


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Posted · Best Answer

That's how CPUs work.

When they need to compute something the frequency boosts up.

Even at idle there are thousands of things happening in the background of a computer.


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Posted · Original PosterOP
Just now, Enderman said:

That's how CPUs work.

When they need to compute something the frequency boosts up.

Even at idle there are thousands of things happening in the background of a computer.

So, to be clear, the idea of a constant or stable downclock during low usage states is simply not a thing in modern CPUs, and I'm also assuming that presumably there is no actual overhead, stress, or additional power consumption or heat generation from rapidly fluctuating frequencies? 


CPU | 8700k @ 5.2 Ghz, AVX 0, 1.4 v Stable, Motherboard | Z390 Gigabyte AORUS Master V1.0, BIOS F9, RAM | G.Skill Ripjaw V 16x2 @ 2666 Mhz 12-16-16-30, Latency 38.5ns GPU | EVGA 2080 Ti FTW3 Ultra HydroCopper @ 2205 Mhz Clock & 8200 Mhz Mem, Case | Phantek - Enthoo Primo, Storage | Intel 905p 1 TB PCIe NVME SSD, PSU | EVGA SuperNova Titanium 1600 w, UPS | CyberPower SineWave 2000VA/1540W, Display(s) | LG 4k 55" OLED & CUK 1440p 27" @ 144hz, Cooling | Custom WL, 1 x 480x60mm , 1 x 360x60mm, 2 x 240x60mm, 1 x 120x30mm rads, 12 x Noctua A25x12 Fans, Keyboard | Logitech G613 Pro, Mouse | Logitech G Pro Wireless Gaming, Sound | Sonos Soundbar, Subwoofer, 2 x Play:3, Operating System | Windows 10 Professional.

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1 minute ago, Daharen said:

So, to be clear, the idea of a constant or stable downclock during low usage states is simply not a thing in modern CPUs, and I'm also assuming that presumably there is no actual overhead, stress, or additional power consumption or heat generation from rapidly fluctuating frequencies? 

If you have no programs running then a clean OS might downclock and stay there for a while, or on low power modes that prevent boosting.

No there is no harm done other than slightly higher temps.


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Do you mean C states? For Intel at least the CPU will have a minimum speed (Haswell is around 800mhz) that it will idle at while using very very little power (under 2W for the whole package) when there is nothing happening. When things happen (mouse moves, background process wakes up, etc) the CPU will change state from say C6 to whatever speed is needed to do the work. Seeing the cores bounce around from .8ghz to a few ghz is normal. If you're running windows check your minimum processor speed in the power plan settings, it should be 0% minimum, there's no reason to not set it to that or none that I'm aware of.

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