Question FPS drops external screen

[Cherouke]

I own a Asus tuf F706HM HX105 (I5 11400, 16GB ram, RTX3600).
I purchased a external monitor to use my laptop as desktop and no longer use the laptop screen.
The monitor is a MSI G27CQ4 E2. I disabled the laptop screen an only have image on the external monitor. However, when playing games the fps drops every couple seconds which makes the game unplayable. Reducing the settings in the game increases the fps but it still drops every couple seconds. (for example from 90fps to 30fps)
First i connected the screen with a hdmi cable but then I saw the hdmi port must be connected with the onboard gpu. So now I bought a USB C thunderbolt cable to dp port. Now the monitor is connected directly to de RTX 3060. But the problem stays. I tried many many settings, nothing helps. I'm clueless right now.
Has anyone a clue what the problem can be?

 

[helpstar]

check temperatures
which resolution and refresh rate are you using on the monitor?
be sure the high performance gpu is used by the game
should be shown in game settings

 

[Cherouke]

check temperatures
which resolution and refresh rate are you using on the monitor?
be sure the high performance gpu is used by the game
should be shown in game settings

I use 1440p. On the laptop it is 1080p. Both are native resolution.
Temperature is ok.
I play mainly world of tanks. I use ultra settings my fps is about 80 tot 90 fps with constant drops to 20-30 fps.
I changed settings tot high in game. This bumps my fps to 130-140 fps with drops to 40 -50 fps.
Even worse sometimes when I am just surfing the internet, the mouse gets unresponsive en starts stuttering.
I bought the USB Thunderbolt to display cable to make sure i use the rtx 3060. With de hdmi cable it showed that it was connected to de igpu first. With new cable it shows it is connected to the rtx 3060.

 

[helpstar]

then something else is odd
check temperatures
to have a look what the problem could be:
run userbenchmark.com and post the http link of your result, e.g. https://www.userbenchmark.com/UserRun/28977730


check windows integrity
open the command prompt as administrator and type DISM /Online /Cleanup-Image /RestoreHealth
https://www.lifewire.com/how-to-open-an-elevated-command-prompt-2618088
https://answers.microsoft.com/en-us...em-files/bc609315-da1f-4775-812c-695b60477a93


clean boot
https://support.microsoft.com/en-us/help/929135/how-to-perform-a-clean-boot-in-windows


check the hard drive for errors with its manufacturer´s tool and if available, update the firmware