Surface Laptop 4 + dock - Mouse & keyboard lag / freeze

Hi all,

I am having the same issue with a brand new Surface Laptop 4 13.5" (32GB/1TB). I am also using a Surface Dock 2 connected to a KVM via USB, with an attached keyboard and a high polling rate mouse. The laptop is running Windows 11 installed clean from USB and all available firmware and software updates have been applied.

I have also experienced the same issue in the past, on a Surface Book 2 connected to the exact same setup. With the SB2, the issue was resolved by following this guidance: https://www.reddit.com/r/Surface/comments/aujg3d/fix_naughty_usbintroducing_a_ridiculous_usb_bug/ 
Unfortunately, limiting the processor frequency on the SL4 did not work as far as I can tell. I continued to look in processor power settings to possibly resolve the issue.

I found that when I set the value of the "Processor idle demote threshold" to 100% the issue was resolved. You can change this value by using this command for "Plugged in" state or AC power:

I make no claims that this is safe to do. You are changing this setting at your own risk.

powercfg -SETACVALUEINDEX SCHEME_BALANCED SUB_PROCESSOR IDLEDEMOTE 0x00000064

To set the demote threshold back to default (40%):

powercfg -SETACVALUEINDEX SCHEME_BALANCED SUB_PROCESSOR IDLEDEMOTE 0x00000028

This did not require a reboot in my testing and the effect is almost immediate. I have set this back and forth for the past few hours and it seems to resolve the issue completely. Not sure what this change means for the idle states or processor power and may completely disable some idle states or all of them.

Same issue here. Brand new Surface laptop 4 32gb Intel i7 with Surface Dock 2. All latest firmware and updates. The mouse lag is driving me bananas.

Wow, this is amazing. This solved my problem.

For the record: I'm on a Surface Laptop Studio running Windows 11 with a Surface Dock 2 running the latest firmware. This was an incredibly frustrating problem that led me to almost return the laptop itself (thinking there were power issues). I spent a week+ on this problem, and ultimately your solution worked. Thank you, thank you, thank you.

(Also to the person who described a symptom as "a key haaaaaaaaaaaaaaaaangs" - amazing - this was happening on my systrem too. It led me to reset to factory settings thinking I had installed some weird software).

This problem was a real head-scratcher - Microsoft, you really, really, really need to address it.

The same happened to me when windows update updated firmware in March to:

• Surface - Firmware (UEFI) - 18.102.141.0
• Surface - Firmware (ME) - 15.0.1879.1
• Intel - System - 2120.100.0.1085

I assume, with what I have read on other posts, e.g. https://answers.microsoft.com/en-us/surface/forum/all/mouse-freeze-on-surface-book-2-after-the-most/df3bee43-c696-4d4f-8b9d-4488dd83870f, that its to do with the UEFI firmware update, but can't say for certain.

I have the same model laptop, an external Logi MX Master 3, but no dock or external keyboard. the issue seems to occur when switching window, or when read / write is happening. It often just stops reading input, and then after a few seconds it inputs the first character typed before it stopped. Its some sort of buffer issue but the fact that it worked before the firmware update is enough to expect a fix.

I've tried removing every troubleshooting step, resetting the system, and also contacted MS support directly who tell me there's no similar issue reported to them, the issue still occurs and makes working on the laptop a nightmare, especially coding.

I am having the issue and I just upgraded to 11 and am having the same issue. There are three of us reporting this issue now. What else you suggest we do beside not hooking a keyboard up to it (which isn't option).

Just frustrated.