Turbo time limit not has no effect - i9-13900hx

[DoDe]

Hi,
I have a strange situation.
For i9-13900hx when I set the PL1=140W and PL2=190W the turbo time limit set at 58 seconds takes exactly as it is set.
But in case I set the PL1=55W and PL2=157W (as the intel specification) the turbo time limit set at 28 seconds takes less then 10 seconds.
Both settings are tested in cinebench.
What am I missing?

 

[unclewebb]

The turbo time limit is not a written in stone kind of number. You will not always get the exact number of turbo boost seconds that you request. Sometimes you might and sometimes you might not. The exact algorithm that Intel uses to determine the turbo boost duration has never been publicly documented. Someone at Intel must know but I have never found any info about this.

I once read a document that compared turbo boost to water in a bath tub. Running the CPU well beyond what PL1 is set to will likely empty the turbo boost tub faster. Full turbo boost will not last as long compared to only running the CPU just a few watts beyond PL1.

That is all I know. Intel is pretty good at hiding their secrets. You need to be a big company and sign an NDA to try and get any info out of them. I am just an individual programmer so I do not have access to any of the good stuff.

turbo time limit set at 28 seconds

For many years 28 seconds was the official recommended value for many Intel CPUs. When they started struggling to keep up with AMD, they bumped the default value up to 56 seconds. This allowed them to be more benchmark competitive. Cinebench R23 completes very quickly so the CPU can run full turbo boost for the entire benchmark.

I think I have had my 14900HX briefly up to somewhere close to 260 Watts before it got hot and started thermal throttling. As long as the CPU is not overheating, I do not think you have to be too conservative with the power limits. No one knows how long the 13th and 14th Gen HX processors will last. If you are running the latest microcode versions, 0x12B or 0x12C, your CPU should be OK for a long time.

Here is an easy way to update the microcode if your laptop manufacturer has not yet updated their BIOS versions.

[INTEL]-How To Update Your Microcode for Intel HX 13/14th Gen. CPUs Laptops/Mobile Easily.

Let me start with a small background info... Since we know all Intel's fiasco about what is happening with Raptor Lake/Raptor Lake Refresh which is Intel's codename for the 13th and 14th generations of Intel Core processors, Most OEM/Vendors doesn't want to provide BIOS update that includes...

www.techpowerup.com

 

[DoDe]

Thanks for the explanation.

I think I have had my 14900HX briefly up to somewhere close to 260 Watts before it got hot and started thermal throttling.

How did you achieve 260W on the mobile CPU since the power brick is 330W and there is a voltage regulator which gives an alarm above 190W for PL2?

Here is an easy way to update the microcode if your laptop manufacturer has not yet updated their BIOS versions.

I'll check it but I thought the problem with 13th and 14th CPU's was related to the desktop once.

I would like to share with you my throttle stop log related to the cinebench stress. Would you be kind to check it for eventual problems? For my little knowledge it should be fine but an expert check is always better.