[SOLVED] R 3800X clock speed all over the place...

davidr123451

Commendable
Aug 20, 2017
7
0
1,510
0
Hey,
Just bought myself a new 3800X and I have noticed that the CPU clock constantly jumps between the 3.8 to 4.5 ghz even when the PC is idle..
Is there a way to allow the CPU to boost only when gaming or on heavy work loads?

using the asus rog X570-I mb with default setting on PBO etc..
 
Hey,
Just bought myself a new 3800X and I have noticed that the CPU clock constantly jumps between the 3.8 to 4.5 ghz even when the PC is idle..
Is there a way to allow the CPU to boost only when gaming or on heavy work loads?

using the asus rog X570-I mb with default setting on PBO etc..
That's the way Ryzen boosting works, I've heard it called a 'rush to idle'.

First, as @mdd1963 suggests, you may not have the same idea of what 'idle' is. In a modern multi-tasking OS like Windows 10 there many different processes and threads running ( I count over 60 in my TaskManager) with many of them constantly asking the CPU to 'DO SOMETHING'. It may be small, but the sooner the CPU can get it done it can throw the core into a deep-sleep state, essentially turning it off, and conserve energy. Zen2 chips do this as often as once every milllisecond.

Second: the processor scales clock on temperature and will always use the highest clock speed it can muster for the temperature. So when one of those little tasks asks for attention Windows' scheduler will throw the thread on an idle core. If cool enough the Zen boosting algorithm immediately boosts to max rated clock, then pulls back as the core gets warm and usually drops away because most likely it's finished in 40 or 50 milliseconds.

For more sustained workloads lasting way longer than 100 or 200 mS, especially hitting all cores, a 3800X clock should settle back to something like 4.35-4.45Ghz. Maybe more like 4.2-4.35Ghz if it's heavy, with some AVX instructions. Even longer and continuous AVX instructions, or anything that heats all the cores substantially, it will drop as far as the base clock speed, 3.9Ghz. Thats assuming you're on something like stock cooling, better and it might be 3.95-3.975. Worse than stock and bad airflow in your case can result in going below base, so less than 3.9Ghz.
 
Last edited:
Reactions: Makaveli
If a new build, what you consider 'idle' ....may not really be truly idle.....

Windows updates could be in progress (a recent one was just passed a few days ago, and folks around the globe will get it in staggered fashion over several days), downloads, cloud storage sync, background malware scans, etc...

Make sure all updates are downloaded/applied before you decide there is or even might really be an issue...

(Get some screenshots of task manager/processes, taking notes of what is eating up CPU resources)

In Balanced Power plan, the CPU should clock itself down to near 800-1200 MHz typically, bouncing around at different clock speeds at several times per second, sometimes peaking to 4.6 GHz for only a moment, or, perhaps all cores at 4.0 GHz or so....
 
Hey,
Just bought myself a new 3800X and I have noticed that the CPU clock constantly jumps between the 3.8 to 4.5 ghz even when the PC is idle..
Is there a way to allow the CPU to boost only when gaming or on heavy work loads?

using the asus rog X570-I mb with default setting on PBO etc..
That's the way Ryzen boosting works, I've heard it called a 'rush to idle'.

First, as @mdd1963 suggests, you may not have the same idea of what 'idle' is. In a modern multi-tasking OS like Windows 10 there many different processes and threads running ( I count over 60 in my TaskManager) with many of them constantly asking the CPU to 'DO SOMETHING'. It may be small, but the sooner the CPU can get it done it can throw the core into a deep-sleep state, essentially turning it off, and conserve energy. Zen2 chips do this as often as once every milllisecond.

Second: the processor scales clock on temperature and will always use the highest clock speed it can muster for the temperature. So when one of those little tasks asks for attention Windows' scheduler will throw the thread on an idle core. If cool enough the Zen boosting algorithm immediately boosts to max rated clock, then pulls back as the core gets warm and usually drops away because most likely it's finished in 40 or 50 milliseconds.

For more sustained workloads lasting way longer than 100 or 200 mS, especially hitting all cores, a 3800X clock should settle back to something like 4.35-4.45Ghz. Maybe more like 4.2-4.35Ghz if it's heavy, with some AVX instructions. Even longer and continuous AVX instructions, or anything that heats all the cores substantially, it will drop as far as the base clock speed, 3.9Ghz. Thats assuming you're on something like stock cooling, better and it might be 3.95-3.975. Worse than stock and bad airflow in your case can result in going below base, so less than 3.9Ghz.
 
Last edited:
Reactions: Makaveli

davidr123451

Commendable
Aug 20, 2017
7
0
1,510
0
That's the way Ryzen boosting works, I've heard it called a 'rush to idle'.

First, as @mdd1963 suggests, you may not have the same idea of what 'idle' is. In a modern multi-tasking OS like Windows 10 there many different processes and threads running ( I count over 60 in my TaskManager) with many of them constantly asking the CPU to 'DO SOMETHING'. It may be small, but the sooner the CPU can get it done it can throw the core into a deep-sleep state, essentially turning it off, and conserve energy. Zen2 chips do this as often as once every milllisecond.

Second: the processor scales clock on temperature and will always use the highest clock speed it can muster for the temperature. So when one of those little tasks asks for attention Windows' scheduler will throw the thread on an idle core. If cool enough the Zen boosting algorithm immediately boosts to max rated clock, then pulls back as the core gets warm and usually drops away because most likely it's finished in 40 or 50 milliseconds.

For more sustained workloads lasting way longer than 100 or 200 mS, especially hitting all cores, a 3800X clock should settle back to something like 4.35-4.45Ghz. Maybe more like 4.2-4.35Ghz if it's heavy, with some AVX instructions. Even longer and continuous AVX instructions, or anything that heats all the cores substantially, it will drop as far as the base clock speed, 3.9Ghz. Thats assuming you're on something like stock cooling, better and it might be 3.95-3.975. Worse than stock and bad airflow in your case can result in going below base, so less than 3.9Ghz.
Thanks for the amazing answer.

my "Idle" temp is currently sitting between the 45-55 degrees on stock cooler.

Air flow is configured as follow :
2*140mm front intake
2*140mm top intake
1*120mm back exhaust

Under heavy work load (2 hours of prime95 for example),
temp never goes above 80 degrees and boost clock never drops below 4.2~ ghz.

But the fan is spinning a bit too loud to my taste.. I have already tweaked the fan curve.

Considering the following info, would u suggest upgrading to an aftermarket cooler ?
for example.. the Dark rock slim from Be Quite! ?
 
...
Under heavy work load (2 hours of prime95 for example),
temp never goes above 80 degrees and boost clock never drops below 4.2~ ghz.
...
That's pretty good to me...my 3700X goes to 3.625-3.650 Ghz at full stock settings on a heavy Prime95 workload (base clock is 3.6Ghz). I have to enable PBO and tweak it a little to get it hold around 4.2Ghz...and that's using a 240mm AIO too! So either you have a pretty good CPU or your motherboard is set up a lot better in stock configuration, which is probably just as much the case as anything else. And then again, I'm not that familiar with 3800X's.

You could probably get quieter operation with high-end cooling, and that's as good a reason as anything else. But if you also enable PBO with some tweaks, along with the new cooling it should settle down even higher. But even if it doesn't, it will be quieter!
 

davidr123451

Commendable
Aug 20, 2017
7
0
1,510
0
That's pretty good to me...my 3700X goes to 3.625-3.650 Ghz at full stock settings on a heavy Prime95 workload (base clock is 3.6Ghz). I have to enable PBO and tweak it a little to get it hold around 4.2Ghz...and that's using a 240mm AIO too! So either you have a pretty good CPU or your motherboard is set up a lot better in stock configuration, which is probably just as much the case as anything else. And then again, I'm not that familiar with 3800X's.

You could probably get quieter operation with high-end cooling, and that's as good a reason as anything else. But if you also enable PBO with some tweaks, along with the new cooling it should settle down even higher.
PBO is enable on "Auto" in bios settings... ain't much of an overclocker so tweaking is out of the question lol. Noise is currently what is concerning me the most, hope a new cooler will do the job.

Edit : typos
 
PBO is enable on "Auto" in bios settings... ain't much of an overclocker so tweaking is out of the question lol. Noise is currently what is concerning me the most, hope a new cooler will do the job.

Edit : typos
oh my...the tweaking is easy....

take it out of AUTO, put it in MANUAL, put PPT to 300, EDC to 230 and TDC to 230.

make sure VCore is left on AUTO and you'll get like 95% of everything PBO has to offer for your CPU. And it's perfectly safe because you're not messing with the core voltage and leaving the boosting algorithm with full authority to pull clocks and voltage as necessary to reduce temperature.

EDIT: and added to make sure get's set: Advanced C States to ENABLED, Cool n Quiet to ENABLED, CPPC to ENABLED and CPPC Preferred Cores to ENABLED. That's just in general, not everyone knows to do so. They should actually be enabled by default but many BIOS's interpret AUTO or DEFAULT to be DISABLED so it's just better to do it.
 
Last edited:

davidr123451

Commendable
Aug 20, 2017
7
0
1,510
0
oh my...the tweaking is easy....

take it out of AUTO, put it in MANUAL, put PPT to 300, EDC to 230 and TDC to 230.

make sure VCore is left on AUTO and you'll get like 95% of everything PBO has to offer for your CPU. And it's perfectly safe because you're not messing with the core voltage and leaving the boosting algorithm with full authority to pull clocks and voltage as necessary to reduce temperature.

EDIT: and added to make sure get's set: Advanced C States to ENABLED, Cool n Quiet to ENABLED, CPPC to ENABLED and CPPC Preferred Cores to ENABLED. That's just in general, not everyone knows to do so. They should actually be enabled by default but many BIOS's interpret AUTO or DEFAULT to be DISABLED so it's just better to do it.
Did the following, CiniBench score actually went go down from the 2130~ to 2060~ .
After installing the new cooler (and learning about the tweaking methods) I'll do some more testing.
Thanks!
 
Did the following, CiniBench score actually went go down from the 2130~ to 2060~ .
After installing the new cooler (and learning about the tweaking methods) I'll do some more testing.
Thanks!
Which Cinebench are you using? I'd suggest using CB 20 because it runs longer and better loads the cores of a Ryzen; you want to see the thermal effects in the score as clocks get lowered through the run. The too-short runs of CB15 can be highly variable as it depends heavily on the thermal state of the processor when it starts.
 

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