I use SwiftKey too. The problem is when you're at the bottom of a page of posts and you want to select some text to quote or reply to. Tried adblockers - the only way to disable the snow is to totally disable java, then you lose the edit box so you can't post.
It's exactly the same problem as last year, it's making the site laggy and almost impossible to use on mobile devices.
(took 20mins to type this, cpu at 95%)
Try UBlock Origin, you can block certain scripts and like that with it so if you figure out which script is making it snow you can disable it and everything else should still work. I use Firefox on a Android phone and tablet and I'm not seeing that kind of cpu or memory load, everything works normally.
Maybe you also need to try FF and see how many things are running in the background eating up memory and cpu cycles.
My old tablet would get totally bogged down because the system memory was 16 gig and it was so loaded up with various programs it would run out of memory and slow down.
I would put everything I could on the micro SD card and it would run better till something would cause it to reload things back to the system memory and I'd have to do it again.
My phone now has 64 gig of memory and my tablet has 128gig so no longer a problem here.