Slack's performance also depends a ton on how much your teams are using it, and how many teams you're on. "reactjis" are one of the worst offenders -- I've had

Slack's performance also depends a ton on how much your teams are using it, and how many teams you're on. "reactjis" are one of the worst offenders -- I've had a channel open with some people messing around with them, and it'll be casually consuming 30% of cpu and 3 gigs of ram on my top-of-the-line macbook. I would have long since deleted an IRC client that was such a poor performer, but unfortunately there's not any good/complete 3rd party slack clients.