From the paper: "we have to use all the GPUs in DGX1 (8 V100 GPUs, each with 16GB memory) for training. We distribute the generator computation task to 4 GPUs and the discriminator computation task to the other 4 GPUs. Training takes ∼10 days for 2K resolution."

As I don't have a DGX1 here, training the 2K resolution net for 10 days on a p3.16xlarge instance (also has 8 V100 GPUs) would cost USD 5875 on AWS. (USD24.48 per hour on-demand pricing * 24 hours/day * 10 days)