A couple of days ago, I upgraded from a late 2015 iMac 27" 4GHz i7 32Gb M395X to a 2017 27" 4.2GHz i7 24Gb Pro 580, and, wow, what a difference in terms of the GPU performance! See attached for some benchmarks. Geekbench 4 - unsurprisingly, not a huge difference given the CPUs involved, but still significant. Look at the others though, 50-100% improvement in frame rates. Amazing! (all @ 1440p) That table doesn't tell the whole story either. I'm seeing the same level of improvement in Hitman, Dishonored 2 and (most importantly for me) DCS. (I couldn't see any benchmarking facility in these.) I was hoping for a 30% improvement, so I am very pleased and impressed. Unfortunately, the one thing that stands out, is that macOS is still way behind Windows in terms of performance. I know these BMs don't use Metal, but Hitman does I think, and the difference is the same in that. Plus Deus Ex: HD showed a similar pattern for me.