Huh, a capsule cluster of 4 M4 minis might cost around $12k and provide more CPU/GPU/ANE/RAM and storage than a maxed out Mac Pro, which would cost more anyway. They probably resell for more too. If you have a defined level of compute and you need a cluster today for performance a Apple Mini cluster might be the fastest and most cost effective way to do it. I should note, the performance and compatibility jump from going with a small server cluster and Nvidia is probably worth 20K too.