User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

Scroll up and down, slowly and/or quickly on a webpage with webrender enabled.

My hardware is a dell xps 15 9560 with intel 620 on 4k display. I have tested this with addons disabled, on a fresh profile, in safe mode, etc and it always happens no matter what I do. I have tried reinstalling the graphics drivers from the vendor website, installing graphics drivers directly from intel, reinstalling firefox, testing on nightly/stable, and other things.

Actual results:

Webpage scrolling is laggy and drops frames a lot. It does not maintain 60fps, and seems to stutter a lot.

Expected results:

The scrolling should be smooth like chromium.

The following post describes this issue quite well:
https://www.reddit.com/r/firefox/comments/mu5tk4/information_for_intel_hd_5xx_and_6xx_gpu_users/

Here is a performance profile I've recorded of this issue (url: https://reddit.com/r/firefox):
https://share.firefox.dev/3gwQzaf

Here is a relevant bug linked in the reddit post (not filed by me):
https://bugzilla.mozilla.org/show_bug.cgi?id=1583881

Here is another relevant bug (filed by me):
https://bugzilla.mozilla.org/show_bug.cgi?id=1689225

Note: this occurs primarily when using the touchpad. It is still present with a mouse, but much less noticeable.

In the title I typoed, it should say "intel 630", but afaik this issue does also affect the 620