I think this comes down to the right tool for the right job. MCIO is not validated or designed for External use, while OCuLink is. MCIO is only validated for 250 connection / disconnection cycles, while OCuLink is rated for 10,000. I also do not believe MCIO supports hotplug, while OCuLink absolutely does. OCuLink is much better suited for an external, frequently disconnected environment.
We likely won’t see (genuine) OCuLink beyond PCIe 4.0, because PCI-SIG is moving beyond OCuLink for PCIe 5 and higher with CopprLink and a yet-to-be-named equivalent Fiber standard. By the time that matters in a mobile solution, we’ll probably be looking at new gear anyways. PCIe 5 and beyond will begin really pushing the limits of utility for external applications without fiber optic cables, as many of these solutions will be sub-1 foot of maximum cable length.
3 Likes