FWIW, the CPU in the C-5 is the same CPU as the C-4, clocked a bit faster (different SOC).
We did look at a faster CPU option. Here's the problem: It didn't make very much difference, and I for one would be p.o'd to pay more for something that didn't perform a lot faster. There's a reason for that: the hub is not, in general, CPU bound. It is I/O bound. You can throw a much faster CPU at it but that does not speed up the mesh networks, or the LAN. Given that most of the reported hub slowdowns are from badly done LAN implementations, a faster CPU would not make any real difference.
We had a batch of bad C-4 hubs, actually a small percentage of one batch of hubs. These hubs were about 1/3 the speed of a normal C-4 hub. As an experiment I moved my home system to one of these to see what impact it had. Guess what, there was no discernible difference in how my Hubitat system functioned. All of my automations were still snappy fast, and I could still do development on it at the same time.
It's just as easy to bring a super computer to its knees as it is a small microprocessor.
