How to turn on Accelerated Compositing Layers on Firefox
https://cialu.net/how-to-turn-on-accelerated-compositing-layers-on-firefox/
http://archive.is/xrBZA
https://web.archive.org/web/20200227075421/https://cialu.net/how-to-turn-on-accelerated-compositing-layers-on-firefox/
Some other potential network tweaks in the about:config menu
network.http.max-connections to 1800.
network.http.max-persistent-connections-per-proxy to 64.
network.http.max-persistent-connections-per-server to 12.
network.http.max-urgent-start-excessive-connections-per-host to 6.
network.websocket.max-connections to 400.
These values are currently double the default values. Whatever your values are, double them and see what happens.
Other Ideas: https://www.greengeeks.com/tutorials/article/increase-firefox-page-loading-speed/