CPU throttling broken for Atom BayTrail CPUs under Windows 10

[idata]

I have reported this already about 8 months ago while being in the insider program over the Microsoft feedback tools, so I am very pleased that this bug still is present in the final version...

The problem is simple, Dell Venue 8 Pro shows this problem. I also have found reports about this on other forums by Lenovo and Asus, so I think it's a problem with the Intel BayTrail or DPTF drivers.

The problem is simple:

1.) Let Windows idle

2.) Open TaskManager (or for example CPUz) and monitor CPU throttling

Under Windows 10, the CPU throttling seems to be broken for at least Intel Atom BayTrail (3700 series). The CPU always stays around 1.3-1.7GHz @ 1-3% CPU load.

The same (normal) idle behavior under Windows 8.1 results in the processor correctly using the lowest energy states between 0.5-0.8GHz.

This results in a way noticeable faster battery drain.

2nd bug, mostly related: The battery drain in connected standby is about 3 times higher (~1.1mW/h), compared to Windows 8.1 (~0.33mW/h). The normal drain, by Microsoft itself, is 0.3mW/h for a device supporting connected standby mode.

Heres a video showing problem 1:

https://dl.dropboxusercontent.com/u/14937594/win10cpubug.mp4 https://dl.dropboxusercontent.com/u/14937594/win10cpubug.mp4

You can see how the CPU throttling is not working properly always staying at mid-highe throttling state of the Atom CPU. Normal throttling would be 0.8GHz.

Here is how it should correctly be:

https://dl.dropboxusercontent.com/u/14937594/normal-idle-throttling.mp4 https://dl.dropboxusercontent.com/u/14937594/normal-idle-throttling.mp4

(sorry for the bad quality)

On my desktop PC and my Ultrabook the throttling work fine, so it seems a problem related to the Atom BayTrail drivers under Windows 10 or a combination of things.

[JHans13]

Many user have the same problem, are you working on a patch for normal cpu idling?

[GAmin]

Same issue here, where's an acknowledgement intel?

[Jose_H_Intel1]

Does the issue persist after the Intel® HD Graphics driver has been uninstalled?

[idata]

I have tried to uninstall the Intel HD Graphics driver via device manager uninstall + remove driver on this device. It results in the device becoming really laggy opening/moving windows, but the throttling problem stays.

[Jose_H_Intel1]

So, it is not a driver issue if it persists after the driver has been uninstalled; is it? Does this happen all the time or when using a particular application?

[idata]

Please look at the video posted on first post. It shows all what needs to be known => CPU does not clock down correctly when idling. I'm not sure why you asked me to uninstall the HD drivers though, I dont think the HD Graphics drivers are related to CPU throttling, I assume some part of the chipset driver or Intel DPTF drivers are. And like you see I am not the only one having this issue.

[Jose_H_Intel1]

Try loading the drivers provided by DELL for Windows* 10. You may also consider updating the BIOS.

http://www.dell.com/support/home/us/en/04/product-support/product/dell-venue-8-pro/drivers/advanced http://www.dell.com/support/home/us/en/04/product-support/product/dell-venue-8-pro/drivers/advanced

[idata]

Those drivers (your Intel drivers) do 1. nothing (are broken, which is this thread all about!?) 2. I have the latest bios 3. it works correctly under Windows 8.1

[idata]

Bump.

[msafw1]

Try to manually configure your idle CPU throttling in Window10.

Right-click "Start", click Power Options. click Change plan settings, click Change advanced power setting, click Processor power management

if you can't see "Processor power management" then unhide it with Regedit. (read a simple tutorial: http://nmilosev.svbtle.com/hidden-power-settings-on-your-windows-81-tablet Hidden power settings on your Windows 8.1 tablet or PC )

Go back to Power Options, and try following configuration:

Processor performance increase threshold = 90%

Processor performance decrease threshold = 33%

Allow throttle state = ON

Processor performance decrease policy = Rocket

Processor performance increase policy = Single

Processor performance time check interval = 50 milliseconds

Processor performance history count = 10 time check interval

Processor performance increase time = 1 time check interval

Processor performance decrease time = 20 time check interval

Press OK

Press "Open Resource Monitor" in Task Manager, check the BLUE line on the CPU graph, this is the throttle level. Tweak the settings until it behave like you wanted it to be. Make the Blue line a bit higher if video had "pop"/"crackle" sound, but lower it as far as you can to reduce heat & save battery, tweak "check interval" if UI felt sluggish, ect (its up to you...)

[idata]

Finally someone who tries to help. Thank you, Ive tried your settings, they didnt do anything though. But the idle lower frquency now seems to be a bit lower, now it jumps between 1.05GHz and 1.45GHz.

I alsoe tried to disable Intel SpeedStep in bios and that results in the CPU going forever in its lowest power state of 500MHz. So it is totally a driver issue, or these settings arent properly optimised for the Atom processor under Windows 10, whatever reason why. It seems the load to processor state isnt translated correctly.

What I find weird is though the kind of jumpes it takes, all between 1.05 and 1,7 even if load is 3%. I know there was some kind of c-state bug with some processors in Windows 8, which this could also be somehow related to.

Any suggestions on optimizing those settings? The bad thing is, there are too many... I had to enable at least 50 settins in the registry of the link you gave me, and I dont know what of those I have to change. For example there are options next to "Processor performance increase threshold" called "Processor performance increase threshold for processor performance class 1" too.

I also went to look under "Press "Open Resource Monitor" in Task Manager, check the BLUE line on the CPU graph, this is the throttle level. " and noticed the blue line is always at or above 100%... is this normal!? https://dl.dropboxusercontent.com/u/14937594/IMG_20151009_001604.jpg https://dl.dropboxusercontent.com/u/14937594/IMG_20151009_001604.jpg

Also why is it at 103%? when it's 3% load? After some random time it is also locked at always 125%... I dont think this is normal, and totally a driver bug I guess?

Here are more people btw having the same issue since beta:

http://answers.microsoft.com/en-us/insider/forum/insider_wintp-insider_perf/windows-10-build-9926-weird-processor-throttling/f4e08610-c1ea-4e3c-bbe1-a409953254d5 http://answers.microsoft.com/en-us/insider/forum/insider_wintp-insider_perf/windows-10-build-9926-weird-processor-thrott…

[msafw1]

I don't know what else I could help, the settings is working fine for me. I have Window 10 Home with Atom Z3735G SoC tablet.

Maybe you could tweak the C-state setting that you mentioned, in BIOS. I remember my lowest C-state setting for my Atom is "C7" (this seem to be the default value). Just don't touch setting with name like "GPIO" or "USB" because its very bad. Usually tablet don't have BIOS reset jumper, so if it couldn't boot; then nothing can be done except claim for warranty & replace motherboard ( ).

The "Processor performance class 1" settings don't do anything for my PC, Laptop, or Atom tablet, so just ignore it.

The "125%" is because your CPU is "boosting". This mean your Window 10 asked for more performance & the processor temperature is low enough to allow it, so it increases your processor's Ghz by 25% because it can. (but I disabled it because my Atom tablet don't have any heatsink and it just cause it to freeze up. I set "Processor boost policy" to 0%).

The settings that contain name like "concurrency" and "parking", control how many core is sleeping. I don't know any good value for it,

[MPop]

After tweaking my setting for one week I found the perfect settings for me, use it as a baseline for your own settings with your Bay Trail Atom CPU.

Note: Most of those setting are hidden by default under Windows 8/10, you have to unhidde them to be able to use it. Follow this tutorial to unlock them: http://nmilosev.svbtle.com/hidden-power-settings-on-your-windows-81-tablet Hidden power settings on your Windows 8.1/10 tablet or PC

[jpozz]

My dell has started throttling, but damn, the HEAT IS INSANE. since updating to 10 it gets so hot the screen starts going CRAZY. heat on 8.1 is fine, but 10 is unusable. gets to high 80's, but does show it'll drop below 1.3ghz. idkwtf. it's killing itself and destroying my hardware.

[MPop]

Workaround: In the 2hidden" setting you an use "Maximum processor state" to lower the Max frequency of the CPU