After updating my OS from Windows 8 to 8.1, I have started to expierience wierd keyboard lag. I mostly notice this when gaming. When I am pressing a key for a longer time, it gets "stuck" for a few seconds, and all other keys become unresponsive. I had this issue last time when I upgraded to Windows 8.1, only this time I don't have mouse lag.

I am using a Samsung laptop with a Microsoft USB keyboard (My main one) connected, because I had some broken keys on my laptops keyboard. Now my laptops keyboard is replaced, but I use the USB keyboard for gaming, because I am used to it.

I have installed all the latest updates, and I am waiting for Windows 10 reservation.

Sorry for my bad english..

I recommend you to uninstall the USB drivers by using the Device Manager console.

https://technet.microsoft.com/en-us/library/cc725782.aspx?f=255&MSPPError=-2147217396#bkmk_1

Then restart the computer and drivers will be reinstalled automatically.

Verify if the problem still exists.

You can already install Windows 10 if you want to by using the Download Tool Now.

https://www.microsoft.com/en-us/software-download/windows10

Does it lag only when playing games?

In addition to the suggestions T.Kujala provided, I also suggest you try to install the software for your Microsoft USB Keyboard to check the issue from the following link:

https://www.microsoft.com/hardware/en-us/downloads

Please also check if other USB keyboard can work normally?

If the issue persists, please also test the issue in Clean Boot to check if there is any software conflicts.

How to perform a clean boot in Windows

https://support.microsoft.com/en-us/kb/929135

Whats the result in Clean Boot?

If it works normally in Clean Boot, please also refer to the following section How to determine what is causing the problem by performing a clean boot.

For Windows 10 upgrade, you may refer to the following forum for more helps.

https://social.technet.microsoft.com/Forums/windows/en-US/home?forum=win10itprosetup

Regards,

Arthur Li

Does this lag only happen in a browser?