Earlier quoted context omitted.
MoE is pretty enabling after you've spent all the extra $$$$ to stuff your server CPU memory channels with ram so it's possible to run at all. But it's still spending a lot of money which makes this a lot less novel or interesting than "just on 1~2 Arc A770" implies. Especially for the marginal performance that even 8-12 channels of CPU memory bandwidth gets you.
Actually, 384GiB is already [1] https://www.amazon.com/NEMIX-RAM-DDR4-2666MHz-PC4-21300-Redu...
The reason they used a Xeon is memory channels. Non-server CPUs only have 2 but modern Xeons have 8 to 12 depending on generation/type. And the Xeons with the most are the most $$$$ and it ends up cheaper to just get a GPU or dedicated accelerator.