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Laptop slows down when inactive

Level 7

I am running a computationally intensive program that will take some time to complete. I have divided the task into many separate Windows console programs, which are equivalent except for the starting values. I have four machines which I have dedicated to the task.

  • A custom built desktop using an Asus 'Supercomputer' motherboard

  • An MSI gaming laptop

  • A Monster gaming laptop

  • An Asus Strix Scar 17 laptop

    all running Windows 10.

I run one program for each thread on a machine, which is easier for me than trying to learn how to write a single multi-threaded program.

Now, my three oldest computers all run approximately the same number of calculations per thread per second. But, ironically, the Asus laptop, which is my newest and most powerful computer, only does about half what that the rest are doing. I was initially thinking maybe it is being throttled due to heat. But whenever I look at task manager the CPU speed is always at maximum. Eventually I noticed that after some specific time away, between 4 and 5 minutes, the Performance graphs show that the CPU utilization drops from 100% to 25%. As soon as I interact with the computer again (i.e. mouse movement) the utilization immediately goes up to 100%. So the problem is obviously not thermal, because it can't magically cool down and go back to normal speed the instant I start using it every time. My other 3 computers have all the same settings but stay at 100%, regardless of whether I am interacting with them or not.

The only thing I can think of is that this must be some kind of 'feature' that reduces power or something if no interaction is detected for 5 minutes, or whatever. I have searched for any kind of setting that could be related to this but have found nothing. I did stop as many processes and services as I could before I started running the programs, so the environment should be as unencumbered as possible. I have looked through all Windows power and other settings and some Asus utilities that came installed, but nothing seems to be relevant, and they're not running in the background anyway.

Any idea what's going on or how I can diagnose the issue?


Customer Service Agent

Hi @Lerner ,

To further investigate your issue, could you please share with us the model of your laptop and the current BIOS version you are using?

Please check the power settings in Windows to ensure that no energy-saving options are enabled that could potentially cause the CPU to throttle after a period of idle time. Try adjusting the processor power management > minimum processor state. If you set the minimum processor state to a higher value (let's say 70%), the CPU will use more processor resources even when idle. By doing this, the system won't let the CPU operate below 70%.

You mentioned stopping many processes and services before running programs. Could you let us know which ones you stopped? Have you tested enabling the stopped services to see if it has any impact?

We hope this information is helpful to you. Thank you.

Level 7

After some research I found out the problem is likely to be related to 'modern standby' or S0 mode sleep. This explains why only my newest computer is affected. This is another ridiculous attempt to not only tell people want they want, but force them to accept it, because there's no way to turn it off. (Which is Windows modus operandi, although I don't think this is a Microsoft initiative.)

I have tried various solutions to try and disable it, but so far nothing works. I can't really do a lot of testing though because I'm a couple weeks into a couple month calculation and I'm not about to reboot my computer and keep restarting from the beginning, slow computer or not.

I have happened upon one solution though. This is to set the screen to never turn off in power options. This does indeed prevent this deliberate performance degradation, but at the cost of leaving the screen on 24/7 for weeks. I know screens are a lot better than CRT's used to be, but still that can't be good. So of course I would like to find a better solution. This obviously isn't going to be a 'follow this procedure' solution, but more like some undocumented hack that someone has come across.

Laptop is an Asus G732LWS-XS98. BIOS version 314 (American Megatrends - 50011).

Customer Service Agent

Hi @Lerner ,

Thank you for your reply. 
Due to Microsoft’s design, Modern Standby mode had been implemented from Windows 10 announced. The system will enter Modern Standby mode after the screen turns off, and it means that the system enters a quick sleep.
When you set the screen to turns off by pressing Fn+F6 or configuring it in power settings,even you already set up “PC never goes to sleep”, Modern Standby will still be activated. 
If you wish to operate at high efficiency for extended periods, it's recommended not to turn off the main screen of your computer to avoid triggering Modern Standby. If you have an external monitor, consider using it and adjusting the screen display to show only on the second monitor to reduce usage of the main screen. This information is provided for your reference. Thank you.

Thanks, Using an external monitor is a good idea.