I'm very curious about this as well. Anyone have any experience?
Adobe, do you have plans to test this new hardware on the iMac platform? Is there a timeline for such testing?
adobe staff typically doesn't respond here with detailed info, so i wouldn't expect any help from them. the amd 500 series is based off the same tech as 400 series, which has been working ok for the most part. this youtube video compares the new imac vs older model, and shows the radeon 580 working fine. perhaps more interesting is how far behind premiere is in performance vs the other software. adobe takes a while to copy features from other NLE's and software, so eventually they might implement the same features and catch up some performance ground.
I've been working in PP CC 2017 with the new iMac running the Radeon Pro 580 and 40gb RAM and have experienced several disappointing issues. The biggest has come when using LUTs with the Lumetri Color panel while editing HD footage I transcoded to ProRes 422. During both playback and export I get random flashes of pixelation with GPU acceleration enabled. Sadly, when I contacted Adobe about the issue, I was told my only option was to edit using the "software only" option and "try" to use GPU acceleration during export and am literally doing this as I'm typing this up - so I'll try to remember to report back on the issue. Kinda sucks and I'm really disappointed in Adobe for not including the Radeon Pro 580 in their list of "approved" graphics cards as they've had plenty of time to test this and send out an update to everyone. As it stands, I upgraded to the new iMac expecting it to speed up my work flow and w/o being able to use GPU acceleration during export - the weekly TV show I produce still takes over 6 hours to export #sad
I am guessing OpenCL will never be as good at GPU Acceleration as CUDA. Even the latest AMD/ATi Vega's are no where near as good as the current nVidia GTX 10 series of products.
Here are the PPBM test results of the two current GPU's with the new top of the line AMD Threadripper 1950X based system
"34","79","27","156", Premiere Version:, 188.8.131.52, Vega Frontier 16GB GPU ($999)
"34","52","13","158", Premiere Version:, 184.108.40.206, Asus GeForce GTX 1080 Ti 11GB ($750)
The first number is the disk test result and the 4th number is the CPU intensive test. The two middle numbers are GPU accelerated tests. Unfortunately this is a PC-only test.