@binyamin Latency (how long does a key press take to cause an action) is most important. also memory is more important than you might expect because many of these (slack in particular) are so fat they can evict things from memory which will make your machine slow enough to be unusable.

Also on windows machines I/O tends to be a premium because there's so much crap from both Microsoft and the OEM eating it so that's another good thing to watch.

Stuff like start up time is good to know but usually not too important.