> How about a sane Profile manager? This is something I use heavily on Chrome. The "about:profiles" UI doesn't cut it.

What's your thoughts on Multi-Account Containers? I think it's better to use if your use case for multiple profiles is to keep sessions separate (i.e., keeping work and personal logins to clearly identifiable tabs / windows)

It's not as thorough compared to switching entire profiles but sometimes the above is sufficient. (ex: your history, add-ons and bookmarks are still under the same profile)

I've always used the -ProfileManager command line option in the past and shortcuts to "-P <profilename>" when wanting to launch/send actions to sessions. (didn't know of about:profiles UI, neat)

I haven't played with MAC (Multi-account Containers) yet but I understand they're a lightweight version of Profiles that can co-exist in a single browser session and have a bunch of neat features (like auto-binding certain sites to certain containers when visited). Would recommend trying out if you've been dissatisfied with the previous approach.

My money would be on you having an ATI graphics card and that being a good bit of the graphics jank.

2013 intel chip+integrated graphics runs like a champ and with lower memory usage than chrome (though I am blocking all the ads, which does significantly change performance everywhere).