I've been plagued for years with a lagging Apple mouse. It seems to lag more every year. I've got a cMP 12 core with a lot of bells and whistles. It plays and edits 4K at 60hz. However, often the mouse can be a half a second--AND SOMETIMES A COMPLETE SECOND--behind. SO MISERABLE. This issue has creeped up over the last five years. I've sorta learned to be more and more patient. Every new OS made the issue subtly worse. UNTIL NOW. I finally had enough. After a day or two of reading up, it turns out that bluetooth mice are just slow. Corded optical is the way to go [laser mice are technically higher resolution but kinda buggy in how they perform in the real world says many reviewers]. Game mice are the way to go. I just received a Zowie EC2-A. WOW I mean WOO HOO WOW OMG WOW I'm zipping through Adobe Premiere like I was on a Quadra 840AV [can I get an Amen? Anyone go back to one of those legendary Macs: the first Mac that could edit SD video at 30fps--if you had the right settings including disabling the clock?]. SIGH... Why didn't I do this years ago? The difference feels like 500% better. Possibly 1000% better. The mouse just moves where it's supposed to move. No delay. Imagine that. Best $60 you can spend on upgrading your Mac. Nothing comes close. Well, ok maybe the difference when you first move from HD's to SSD's comes close--it's THAT kind of different.