The bad performance you saw was with very limited memory and very large models, so streaming weights from storage was a huge bottleneck. If you gradually increase RAM, more and more of the weights are cached and the speed improves quite a bit, at least until you're running huge contexts and most of the RAM ends up being devoted to that. Is the overall speed "usable"? That's highly subjective, but with local inference it's convenient to run 24x7 and rely on non-interactive use. Of course scaling out via RDMA on Thunderbolt is still there as an option, it's just not the first approach you'd try.