Prime95: CPU switches frequently between basic and turbo frequency. Is this normal?

[Kalidus]

Good day to all of you. I just registered and am looking forward to getting to know you.

 

I asked the same question in a German tech board before, but we couldn't find a suitable solution yet. 

 

I built an entirely new pc over the weekend, containing the Ryzen 9 5900x (basic & turbo frequency according to AMD: 3.7GHz / 4,8Ghz). My main focus is to achieve a stable system for post-production & rendering (no OC).

 

If I run Prime95, the 5900x starts with the turbo frequency of 4500 MHz per core. But after 6-10 minutes, the CPU falls back to the basic frequency of 3500 MHz. After another 5-10 minutes the core speed rises again to approx. 4500 MHz. This circle repeats in a similar pattern until I stop Prime95.

 

The main problem is that I don't know what to expect of my CPU. I thought the turbo frequency kicks off under load and stays activated until the actual task is finished. As Prime95 confronts the CPU with a constant load, I expected the CPU to remain in turbo mode most of the time. Was this assumption incorrect?

 

Thanks to an adaptive fan profile, my CPU's temperature under load stays relatively stable (approximately 65-72°C for basic and turbo frequency). When clocking up and down, the CPU shows temperature spikes of up to 88-90°C though.

 

Is my CPU's behavior normal, or am I witnessing some form of thermal throttling? Should I ramp up the fans?

 

I appreciate your help,

 

Jan

[Prodigy_Smit]

Ok so it appears that you system is thermal throttling and then recovering the temps and then throttling again when the temps get out of hand.

What cooler do you have?

[wall03]

2 minutes ago, Prodigy_Smit said:

Do you have?

???????

[Prodigy_Smit]

3 minutes ago, wall03 said:

???????

Ooops updated the post.

[Kalidus]

3 minutes ago, Prodigy_Smit said:

Ok so it appears that you system is thermal throttling and then recovering the temps and then throttling again when the temps get out of hand.

Do you have?

So you say, normally the CPU should stay in turbo mode for an hour or longer?

 

I had the feeling my temperatures are in general not too high, as AMD stated regular temperatures of up to 90°C for the 5900x. 

 

Could this be a cooler problem?

[Prodigy_Smit]

Just now, Kalidus said:

So you say, normally the CPU should stay in turbo mode for an hour or longer?

 

The CPU should turbo as long as temps are good.

1 minute ago, Kalidus said:

I had the feeling my temperatures are in general not too high, as AMD stated regular temperatures of up to 90°C for the 5900x. 

 

90C is like when it starts throttling so under that is better.

1 minute ago, Kalidus said:

Could this be a cooler problem?

Which cooler do you have?

[Kalidus]

Just now, Prodigy_Smit said:

The CPU should turbo as long as temps are good.

90C is like when it starts throttling so under that is better.

Which cooler do you have?

Be quiet dark rock Pro 4.

 

Maybe I should reinstall? But most of the time its like 60-70°C under load (50°C over room temperature). These temperature spikes come quite abbrupt and stay only for like half a minute. I assumed them to be not the cause for the frequency adjustments but to be more of a byproduct of the regulation process itself.

[Prodigy_Smit]

3 minutes ago, Kalidus said:

Be quiet dark rock Pro 4.

 

Maybe I should reinstall? But most of the time its like 60-70°C under load (50°C over room temperature). These temperature spikes come quite abbrupt and stay only for like half a minute. I assumed them to be not the cause for the frequency adjustments but to be more of a byproduct of the regulation process itself.

Oh well since the temps are around 60-70C they seem to be normal. In that case I dont think there is a problem. But I would remount the cooler since those spikes should not happen.

Just now, Kalidus said:

Most of the time the cpu switches from turbo to basic mode when the temperature reaches like 82°C (62 over room temperature). The spikes around 88-90°C only occurs when the CPU is switching from basic to turbo mode.

That is high remount the cooler.

[Kalidus]

3 minutes ago, Kalidus said:

Be quiet dark rock Pro 4.

 

Maybe I should reinstall? But most of the time its like 60-70°C under load (50°C over room temperature). These temperature spikes come quite abbrupt and stay only for like half a minute. I assumed them to be not the cause for the frequency adjustments but to be more of a byproduct of the regulation process itself.

Most of the time the cpu switches from turbo to basic mode when the temperature reaches like 82°C (62 over room temperature). The spikes around 88-90°C only occurs when the CPU is switching from basic to turbo mode. Weird.

 

I might try to reinstall the cooler. Thanks! 

[Person_125]

I agree with @Prodigy_Smit, try reinstalling the cooler.