The new Apple iMac Pro will feature Radeon Pro Vega graphics solutions. The specs published by Apple reveal some interesting details.
Radeon Pro Vega 56 and Radeon Pro Vega 64
As you might remember Radeon R9 Fury series were using two Fiji variants, either 4096 cores (64 CUs) or 3584 cores (56 CUs). As it turns out, AMD may follow the same path with Vega, as confirmed by Apple iMac Pro specs.
New iMac will be equipped with Radeon Pro Vega 56 with 8GB HBM2 memory or Radeon Pro Vega 64 with 16GB HBM2 memory. The model numbers are likely referring to NCU count, which means AMD is already planning cut-down chips with 3584 cores, same as Radeon R9 Fury.