What's the best Mac computer configuration for using sketchup 2017?

What’s the best Mac computer configuration for using sketchup 2017 ?

• CPU: intel Core i7 quad (high clock freqency better than multiple CPUs)
• GPU: nVidia GeForce GTX
• RAM: min. 8 GB
• Volume: SSD

That is almost the exact config I have in a 21.5" iMac with 16GB ram and it is fantastic.
To compare, I also have another 21.5 iMac but i5 quad, Retina and standard drive; it is nowhere near as fast or smooth.

If you can afford it, I find the iMac 5K Retina 27" with the AMD Radeon R9 M395 2GB works very well too.

AFAIK I’ve had no graphics issues with it, though I’m not a regular user of Layout, which I understand has had some blocky display problems with some AMD cards - though I don’t think this one has that problem.