System specs
MacBook Pro 15" Mid 2018 "MacBookPro15,1" (A1990)
2.6 GHz six-core Intel Core i7 Coffee Lake (8850H), up to 4.3 GHz
16 GB DDR4
AMD Radeon Pro 555X
Intel Iris Plus Graphics 630
MacOS Catalina 10.15.1
256 GB SSD
eGPU hardware
AMD Sapphire Pulse RX 580 8GB GDDR5
Apple TB3 cable to eGPU
Display port cable to Samsung UE590 28" 4k monitor
Installation steps
None. Natively supported.
Benchmarks
I bought this egpu purely for 4k video work in davinci resolve. I did perform some gaming benchmarks for fun.
Metal Internal 555x Geekbench - 13570 score
OpenCL Internal 555x Geekbench - 12959 score
Metal RX 580 Geekbench - 33468 score
OpenCL RX 580 Geekbench - 38635 score
Unigine Heaven RX580 - 1432 score, 56.9 avg fps, 1080p, Quality Ultra, Tessellation Disabled, Min fps 14.4, Max fps 94.3
Davinci Resolve 16 Export Benchmark: I exported A 1 minute 4k timeline using h.264 footage exporting to the youtube 4k preset. I did not use proxy files or render cache. All project files were living on the internal SSD. Fwiw, I performed all the tests with an external SSD and the times were nearly the same.
Using Metal and all available GPU's resulted in a 1:45 export time.
Using only the external gpu with Metal took 1:57.
Using only the internal 555x with Metal took 2:37.