Hi there, not a question but I wanted to put this out there for those who may be running into the same issue as me. I hate searching for things and not finding a straight answer, and I'm hoping that I can bring light to others who may be undergoing the same issue. I was infuriated by YouTube (and only YouTube) and how slow it was to respond to pretty much any command I sent via my keyboard. Clicking was fine, but if I wanted to skip 5 seconds in the video by mashing the right or left arrow a bunch, it would buffer those key presses and then register all at once. Basically, YouTube was lagging out of its mind and decided that any kind of action I wanted to take on the page would be done incredibly slowly (by modern computing standards, so ~700ms). I play rhythm games, so any input delay more than about 2ms will annoy me to no end. This ended up being something called GC or garbage collection, and it was "minor GC" and "non-incremental GC" and something to do with a Nursery being full. Whatever that is, switching over to the Call Tree function in the F12 performance menu (F12>Performance>Start Recording Performance>*input commands on video*>Call Tree) told me that the function GC was taking up around HALF of my time recorded. This gave me a place to start at least, and I'm glad that Firefox has this feature and that it's user friendly. I know NOTHING about webpage design or coding, and it wasn't that hard to figure out what was going on. Expanding the menus was helpful, and I found out that it was actually my Kaspersky Antivirus causing the issue. I dug around for another hour or so and found this [https://blog.lakshmanbasnet.com/web/website-slow-connecting-to-gc-kis-v2-scr-kaspersky-labs-com-solved/ helpful article] on how to fix it. A TL;DR from that article is, if you have Kaspersky, go to Settings>Additional>Network and untick "Inject scripts into web traffic to interact with web pages" This script injection was doing something to slow it down, most likely trying to scan and monitor the inputs I was making on YouTube to be sure I wasn't getting myself into any trouble. Hope that this helps anyone else having this issue, and any moderation can mark this as solved.