Hey there.
If its not about money but only performance, you could give some regular x86 devices a try. Lets say the intel NUC or something. I have no clue if the OpenWRT x86 build has USB driver support for those but there's a chance that's gonna be awesom in terms of performance.
But deciding on hardware without knowing the exact requirement is uselsss.
So could we please start with: What exactly is the problem to solve?
Maybe sticking to OpenWRT isn't the best way to go, either. As long as OpenWRT mainly targets low powered SoHo devices, having a SoHo grade OpenWRT device for routing, firewalling, switching and stuff on one hand and having an enterprise server class node for computing tasks on the other hand might be the better choice in terms of both, price and resource usage.
I do run a TP-Link 4900 as WAN gateway with a couple of vlans, two other TP-Link 4900, a TP-Link 4300 and a TP-Link 1043 as hot spots all connected to an Intel i5 CPU 16GB RAM 2TB hardware RAID host running ESX for "service" like webserver, samba4 domain controller, a routing/NATing OpenWRT instance and some other VMs.
Having only one device for those things would neither be sufficient in terms of wifi range, nor in terms of computing performance.
By the way: I really doubt pure CPU and RAM has anything to do with number of devices connected. I can set up a single client computer doing torrent stuff that just eats up whatever hardware you come up with. Once I had a single Macbook (one of 50 device) connected to an Astaro on bare metal Xeon 4*2.5GHz that alone used 50% CPU on that router. Ok, that was a dum misconfiguration of that Macbook doing local loopback through a proxy connection. But that clearly shows: You just cant provide enough hardware to never worry about utilization.
If its only about regular use, the number of wifi clients isn't limited by computing power but by wifi capacity. So just having a huge number of hot spots utilizing every wifi channel you can get usually is the far better choice. This means: Lots of low powered hot spots to reduce overlapping.
The thing I want to tell you with this essay: Just asking for "the most powerfull hardware one could imagine to run OpenWRT on" isn't exactly answered easily and really depeonds on what you want to do.
And to give the initial post of this thread a straight answer: No, the C9 isn't supported. The C5v2 as well as the C7 are supported (there are rumors of them to be equipped equally), but they have less CPU.
Regards,
Stephan.
(Last edited by golialive on 29 Jun 2015, 21:13)