Perceptions... A few months ago I bought a new MacBook Pro to replace my aging (2014) MacBook Pro. Aside from the gimmicky (and, to me at least, confusing) touch bar, I really like the new machine. I especially liked the added SSD disk space (I got the terabyte version) and RAM (I maxed it out). My old 2014 box has been sitting on a shelf (literally), unused since the day I got the new machine. I kept it nearby in case something screwed up on the transfer I did to move all my stuff to the new machine ... but nothing went wrong; it “just worked.”
So today I picked up the old machine, dusted it off (it was awful!), and brought it into the house to see if it might be convenient to have for use there. I've been “iPad-only” in the house these past few months, and that definitely puts some restrictions on what I can do. I plugged it in, let it charge for a bit, then booted it up. Everything still works fine, as expected. What I didn't expect, though, was that I'd perceive it as slow!
Now my 2017 MacBook Pro really is a faster machine by the specs, but not all that much. The speed improvement wasn't big enough to catch my attention as I started using the new machine. But ... in going back to the old machine, I'm noticing all sorts of places where there's just a tad more time being taken to do something. A couple operations are much slower – for instance, opening my morning reading list (with 46 tabs) takes roughly twice as long on the old box. Isn't it odd that I didn't particularly notice the speed-up, but did notice the (same) slowdown?