Depends what you're trying to do, of course. But if your goal is to scale solving a single problem across many comouters, you need an interconnect that can keep

Depends what you're trying to do, of course. But if your goal is to scale solving a single problem across many comouters, you need an interconnect that can keep up with your CPUs and RAM. Which means preferrably > 40 Gbps, and then you need those PCIe lanes. 100 Gbps is getting close to affordable these days; in fact dirt cheap if you're willing to mess with weird stuff like OmniPath.