For quad GPU config you should look at dev box type option. It's $8,750 for machine with 4 1080Ti, 64GB of RAM, and 1TB SATA SSD. Quite a steep margin if you ask me, considering a 128GB RAM machine that you build yourself would cost you at most $5,700 (taxes included) if you get everything from Amazon, and probably under $5k if you're willing to shop around a little.