Late 2015 iMac 5K: diglloyd Photoshop Benchmarks
Get the new iMac 5K at B&H Photo and see the MPG computer gear wishlist.
Save money on 32GB or 64GB OWC memory (about $400 savings vs Apple!)
MPG recommends this iMac 5K: 27" Retina 5K Display, 4.0 GHz Intel Core i7 (Skylake), 1TB Flash, 8GB memory, AMD Radeon R9 M395X GPU (4GB GDDR5) + 32GB or 64GB OWC memory.
The late 2015 iMac 5K runs neck and neck with a 3.3 GHz 8-core Mac Pro (faster than any Mac Pro that Apple sells). Impressive gains for the iMac 5K: looks like Photoshop jockeys have found the right machine: an iMac 5K with 64GB memory. At least if the tasks are not those oddball ones that actually use 8 or 12 cores.
iMac 5K (Late 2015): diglloyd Photoshop Benchmarks

late 2015 iMac 5K 4.0 GHz, 1TB SSD, M395X vs others