I once switched from Firefox to Chrome on old PCs because Firefox felt intolerably slow. I still use some of these PCs, including semi-old ones on which Firefox feels tolerably slow so I use Firefox. I expected Edge to be at least as as fast as Chrome but no, it feels more slow than Firefox. It also asks many questions (no, I don't want to make it the default nor to sign-in, nor to let it itself cookie-track me, and…
I wonder if the "new" Firefox is about as good on old PCs as Chrome as it improved quite a lot with Quantum/Photon. For me the switch to Chrome was also caused by the abysmal performance of Firefox at the time, but I immediately switched back when the performance was at least tolerable. Granted Chrome is still the faster browser from what I've seen in benchmarks and reviews.
On old PCs - not much, just slightly better. Perfect on modern PCs though so I se no reason (other than testing) to use Chrome on non-museum computers.