Urp 10.4.0 severe perfomance drop

Hi all,

Sorry for one of those performance related threads - but I am pretty much stumped at the moment.
Last week we updated our game from 2019.4 to 2020.3.1f1 and updated to URP 10.3.2 (and later to 10.4.0).

After some template fiddling we had our new build up and running. However we're now experiencing a 40% performance drop over the previous version. The game is quite optimized already and the 2019.4 build was able to run fullscreen with all settings to high and MSAA to 8x at a steady 60fps on a decent computer. The same computer(s) now drop to around 36fps. Drop occurs in both latest versions Firefox and Chrome.

I have been tracking down the perfomance loss for a couple of days now - but I can't find anything that could be the cause.

At this point the only things I can see or think of is that MSAA seems much slower or is more performance intensive then before. In the previous version we could easily go up to 8x without any noticeable drop - now it drops at least 10%.

The other thing is we're rendering a realtime cubemap for reflections - turning this completely off restores a lot of performance. The script however is optimized heavily. Camera renders no shadows, no hdr, no msaa, no post, no opaque, no depth, farclip at 100, culling mask to 2 layers and we only update the sides that are pretty much in view. However the drop is so massive that it leads me to believe there is something throttling the rendering?

Is there anyone who has experienced (similar) performance loss in URP 2020.3?

- Pieter