[SOLVED] i5 6400 not turbo boosting under load?

[alico777]

Hi, so I have an i5-6400 for 2 years now. Its base clock is 2.7 GHz and turbo is 3.3 GHz. Recently I found out by looking in the task manager and after that checking in the CPU-Z also, that while I play games my cpu is boosting only to 3.08 GHz and no more. Also when I run a stress test in CPU-Z I have the same issue. HOWEVER when I'm using a web browser and my CPU usage is around 5-10 % I am getting somewhere from 3.25 GHz to 3.29 GHz.
I donť know what's the problem when the CPU is under load, my temps when under load are stable at 42 °C. And in my BIOS I have the voltage managment set to auto. Do you think I should up the voltage or something? As far as I remember it worked fine at least 6 months ago and I haven't made any changes in my hardware since then.
I'll be glad for anyadvice thanks a lot!

 

[jeremyj_83]

The boost will be affected by how many cores are active. The 3.3GHz boost is probably single core boost and the 3.08GHz boost will be the all core boost. Your boost speed is also affected by thermal load and available TDP. Here is a good article on TDP https://www.anandtech.com/show/13544/why-intel-processors-draw-more-power-than-expected-tdp-turbo
Here is a good page about Intel's boost behavior - https://www.anandtech.com/show/1487...ing-perception-with-amds-frequency-metrics-/2

 

[alico777]

The boost will be affected by how many cores are active. The 3.3GHz boost is probably single core boost and the 3.08GHz boost will be the all core boost. Your boost speed is also affected by thermal load and available TDP. Here is a good article on TDP https://www.anandtech.com/show/13544/why-intel-processors-draw-more-power-than-expected-tdp-turbo
Here is a good page about Intel's boost behavior - https://www.anandtech.com/show/1487...ing-perception-with-amds-frequency-metrics-/2

Thanks for your answer. According to HWMonitor I am getting 3.29 GHz on all cores while using my web browser. And same with the stress scenario, 3.08 GHz on all cores.

 

[jeremyj_83]

Thanks for your answer. According to HWMonitor I am getting 3.29 GHz on all cores while using my web browser. And same with the stress scenario, 3.08 GHz on all cores.

That means that you are hitting extended TDP limits. The longer your CPU is at boost speeds, the more of its TDP budget it uses. Stress tests are always longer than a bursting application on the web, so you will eat into the TDP budget and the CPU will down clock to lower boost levels.

 

[k1114]

I5-6400, 2.7 GHz, 4/5/6/6 bins. This means:
1 core 3.3ghz
2 cores 3.3ghz
3 cores 3.2ghz
4 cores 3.1ghz

3.08 and 3.29 get rounded up. Most mobos default bclk to 99.8 rather than 100.

Btw tdp is heat not power. They are about equal because of how transistors work but to say thermals and tdp is saying temps and temps. Getting to 3.3 web browsing but 3.1ghz on a stress test is all about cores not tdp or power. Desktops that stay cool enough will turbo indefinitely.

 

[alico777]

That means that you are hitting extended TDP limits. The longer your CPU is at boost speeds, the more of its TDP budget it uses. Stress tests are always longer than a bursting application on the web, so you will eat into the TDP budget and the CPU will down clock to lower boost levels.

The CPU speeds go down to 3.08 GHz instantly when I start the stress test, and also there is no difference if I have my fans to full speed or at low so I should not have any thermal problems.

 

[alico777]

I5-6400, 2.7 GHz, 4/5/6/6 bins. This means:
1 core 3.3ghz
2 cores 3.3ghz
3 cores 3.2ghz
4 cores 3.1ghz

3.08 and 3.29 get rounded up. Most mobos default bclk to 99.8 rather than 100.

So do I understand corectly that when I'm using an application that is using all cores I won't get the boost frequency up to 3.3 GHz?

 

[k1114]

Yes, all cores is just 3.1ghz. If you run the stress test to use less cores, you will see the higher speeds.

 

[mdd1963]

Those are indeed normal 6400 clock speeds/behavior...

I think we are done here.