I upgraded to 20.04 LTS about a week ago and have been experiencing very laggy performance since.

There seems to be a slight but perceptible lag with keyboard input and with general performance (moving between tabs in my browser etc).

GPU: I'm running the Gigabyte GeForce GTX 1050 Ti Windforce OC 4G as my GPU.

Desktop environment:
LXDE

NVIDIA driver: nvidia-driver-440 (proprietary, tested) automatically installed during the installation.

How can I go about diagnosing whether this is an NVIDIA driver issue, a hardware issue, or something else?

(Recreating this thread
as I mistakenly prepended the [SOLVED] tag)