I wonder what those who complain about the X5000 being 'slow' actually want to do with the machine?
I didn't complain, I simply stated a fact: X5000 = slow. Somebody asking for advice on a 2300 Euro purchase deserves some honest advice, no?
You don't mind slow? You don't use it to do anything useful so you never notice it's slow? You're so old you don't see the difference between FullHD and a 320x200 video? You never browse the web so you don't witness the single core machine that doesn't have a decent Javascript interpreter slow down to a crawl? Fine by me - I'm happy for you. But don't get all worked up because I call it 'slow'.
The power of the average PC/CPU is generally wasted nowadays.
The last time we got somewhat reliable, independent benchmarks, there was an Mplayer benchmark (decoding a h264 stream) where the MorphOS machine spent 0.6 seconds waiting for system I/O, while the OS4 machine spent nearly 1200% of that time waiting for system I/O.
That's what I call wasting CPU cycles. Granted, that was back in 2012 - but OS4 and drivers aren't exactly a success story.
and even in these examples many tasks are offloaded to the GPU nowadays
Not on OS4.