Laptop lag/high fan speed with low CPU temperature

Hi,

A few months back I have bought a 4k/60HZ monitor that I am using with my laptop (with a FullHD display). It is plugged in via a USB-Hub that connects to the laptop via Thunderbolt/USB 4 port. The problem is that sometimes after a while, usually when watching videos, eg youtube on laptop screen (as a secondary screen) and something else on the primary (4k external monitor), the fans all of a sudden rev up and everything starts lagging massively. This almost always happens when on a long video/conference call. CPU gets also pretty high, however, the CPU temp seems very low (under 50 deg C).

Other hardware connected to the USB hub are:

• ethernet
• speaker

What could be causing this issue? I have tried reinstalling linux. Switching to GNOME from XFCE. None of it helped. This is my laptop specs:

OS: Arch Linux x86_64
Host: 82BH Yoga 7 14ITL5
Kernel: 6.5.8-arch1-1
Uptime: 18 mins
Packages: 760 (pacman)
Shell: bash 5.1.16
Resolution: 1920x1080
DE: GNOME 45.0
WM: Mutter
WM Theme: Adwaita
Theme: Adwaita [GTK2/3]
Icons: Adwaita [GTK2/3]
Terminal: gnome-terminal
CPU: 11th Gen Intel i5-1135G7 (8) @ 4.
GPU: Intel TigerLake-LP GT2 [Iris Xe G
Memory: 2721MiB / 15795MiB