iMac 21,5-inch 4K, what gear should I buy?
@alemonti, The 5700 XT is amazing I have one it works really well
I use it on a Mac Mini though, but it should also be fine on an iMac, just keep in mind what i5 said about the looping back to the internal display, some apps don't work well doing that and there will be a performance hit compared to running an external display -- other apps are capable of using the eGPU directly for computational tasks and don't care if there's a display hooked to it or not, it depends.
Mini-i5 is right though about VM's -- there's no way to "pass through" an eGPU to a virtual machine while running Mac OS unfortunately, and with talking to both the VMWare and Parallels people about this, there most likely never will be.
So how it works is the Hypervisor spawns a metal process on the host machine and certain accelerated gfx functions from the VM get sent to that metal process via a translation layer. The performance hit is pretty massive because of this translation layer, you're better off just running Windows via Boot Camp.
I couldn't get over the idea of spending more for a more powerful card that I may not use to its best potential nor missing out on performance with the cheaper one. So I've ordered both cards off Amazon (they had returns eligible till the 31st of January). I'll do some testing and later upload on the forum my setup and findings.
Thank you again!