SB2 13" - CPU clock speed reduces dramatically under load

[viktormoon]

Hi guys,

2 weeks ago I got the Surface Book 2 with i-7, 16gb ram and 1tb SSD.

When the CPU is idling, or dealing with less intensive tasks it sits at a speed around 3,5GHz which is fine.
But, my need for this machine, and the reason why I took the top model Microsoft offer, is because I need it for video encoding.
Every time I start the video encoding the CPU load increases to a place between 60-95 % which is expected and normal, but the CPU speed throttles down to as low as 1,2 GHz, which is not as expected.
On my Desktop edit machine it's exactly the opposite. Low CPU usage when just idling and doing browser stuff, and then when the muscles is needed it throttles up!

Is this really working as intended?
Or what is going on - Heat issues, power saving or something else? Do I fail to understand how this specific CPU operates?

I tried to get an answer from multiply Microsoft support workers, but they don't seem as informed as I would hope.

best regards
viktor

 

[aod81]

Hi guys,

2 weeks ago I got the Surface Book 2 with i-7, 16gb ram and 1tb SSD.

When the CPU is idling, or dealing with less intensive tasks it sits at a speed around 3,5GHz which is fine.
But, my need for this machine, and the reason why I took the top model Microsoft offer, is because I need it for video encoding.
Every time I start the video encoding the CPU load increases to a place between 60-95 % which is expected and normal, but the CPU speed throttles down to as low as 1,2 GHz, which is not as expected.
On my Desktop edit machine it's exactly the opposite. Low CPU usage when just idling and doing browser stuff, and then when the muscles is needed it throttles up!

Is this really working as intended?
Or what is going on - Heat issues, power saving or something else? Do I fail to understand how this specific CPU operates?

I tried to get an answer from multiply Microsoft support workers, but they don't seem as informed as I would hope.

best regards
viktor

This would be the GPU under task manager doing the heavy lifting. This is completely normal. This is not surface book specific but discrete gpu specific, its usually when NVENC is available on a video card, paired with GPU accelerated SOFTWARE.

 

[wynand32]

This would be the GPU under task manager doing the heavy lifting. This is completely normal. This is not surface book specific but discrete gpu specific, its usually when NVENC is available on a video card, paired with GPU accelerated SOFTWARE.

I was going to answer similarly. If it's an application that can utilize the GPU, then the CPU won't be maximized. However, if it's an application that does NOT use the GPU, then the CPU should be maxed out. As you indicate, you can check out the Task Manager to see which GPU, if either, is being used.

 

[viktormoon]

I was going to answer similarly. If it's an application that can utilize the GPU, then the CPU won't be maximized. However, if it's an application that does NOT use the GPU, then the CPU should be maxed out. As you indicate, you can check out the Task Manager to see which GPU, if either, is being used.

Dear Wynand32,
Simply no. I encode primairly RED footage that is CPU dependent. The GPU only kicks in brief moments pr. frame, as intended, to help with color work, plugins and effects.
The rest is purely CPU driven. Furthermore, I ofc have tested with benchmarks and stress tests as well, where it is the same story.
And still, if you are right - why would the CPU load maintain at 100% and the CPU clock speed go down? That makes no logical computing sense.
There is for sure a down throttling mechanism in order for this machine to not overhead when exposed to demanding CPU requests for a long duration.
I do not live, nor work in a warm climate, so this effect just shouldn't kick in so hard that it throttles down to less than what the CPU is rated for = 1,9 GHz. Then it must be a design flaw. Which I am leaning towards more and more

 

[wynand32]

I'll run a test or two and see if I can duplicate this. I do benchmarks with Handbrake (which doesn't use the GPU) and so I have that handy (no near-pun intended), and I don't remember it acting like you describe during my tests. But I'll run some encodes and see what happens.

 

[wynand32]

Okay, so I ran a test encoding a 420MB file to H.264 using Handbrake, with the SB2 15" power slider at "Best performance." It took roughly 11 minutes, and throughout the process the CPU was pegged at 100% and it varied between 2.2GHz and 2.6GHz.

 

[aod81]

Okay, so I ran a test encoding a 420MB file to H.264 using Handbrake, with the SB2 15" power slider at "Best performance." It took roughly 11 minutes, and throughout the process the CPU was pegged at 100% and it varied between 2.2GHz and 2.6GHz.

A surface book 2 will be arriving tomorrow and I test with certainty. My experience with several software application indicates its up to the software. I had a trouble call in with adobe premiere or media encoder 2018 etc with 4k editing doing similar throttling and making hardly any use of the gpu and not taking advantage to all the cores ryzen 1800x offered up. Simply it was a flaw in adobe. I have since used several other video editing programs for 4k that utilize GPU 4k h.264 to hevc h.265, that being said, Ill be more specific. DVDFAB is my video encoder for 4k to 4k. I have tested tons of other apps all that fail to utilize gpu. The situation with adobe though bothers me because there is no rhyme or reason why it throttled me both cpu and gpu. Dvdfab x64 should be tried just to test the gpu/cpu (options are available to use either or)...although its very expensive there is a 30day trial...

 

[RoadXY]

You could try and install the Intel Extreme Tuning Utility.
See these YouTube movies for more information:
youtube surface book 2 throttle - Google Search

 

[aod81]

As suspected. DVDFAB not only encodes fast, but it is very close to my ryzen 1800x w/ 1070. Not bad for a laptop. Example Desktop goes to 132fps the SB2 hits 107. I believe also that the intel chip that UHD gpu maximizes the benefit of 1050 in my case. I saw both gpus being utilized and about 30% of cpu. If we could get more granular with what software isn't working that would be helpful.

 

[Orlbuckeye]

Remember the new 8th generation i7 is quad core but is still uses the Core™ i7-8650U quad-core processor the U which stand for Ultra Low power. It's built for mobility which has lower temps, longer Battery life then the H family of Intel Processors.

Surface Book 2 Video Editing Review

Also from a review on video encoding, Here are the results of comparing the 7th gen Intel i7 to the 8th generation in the SB2.

For productivity performance, I routinely put my review PCs through a video encoding test in which I use Handbrake to convert a 4K video called Tears of Steel 4K to 1080p using the app’s “Super HQ 1080p 30 Surround” preset. And this confirmed a theory I had about the move from dual-core to quad-core CPUs: Surface Book 2 indeed performs far better than its predecessors in real-world power user tasks.

That is, Surface Book 2 finished nearly neck-and-neck with the previous portable PC champion, the Dell XPS 15, on this test. Surface Book 2 converted the video in almost exactly one hour, just behind the Dell, which finished in 54:29. That Dell, you may recall, sported a quad-core Intel Core i7-7700HQ processor and the same dGPU as Surface Book 2, so it’s a great comparison. And it suggests that Intel’s newer generation U-series chips are now basically the equivalent of the previous-generation HQ-series chips.

By comparison, Surface Book with Performance Base required 1:34 to convert the video. That’s over half again as long, and about average for portable PCs based on a dual-core U-series chip.