The hashing boards are S3 boards with little to no revisions. [See
here for the S3 board]
The controller is S4 in architecture but its not the same board. [See
here for the S3 controller and
here for the S4 controller.]
The C1 controller appears to be based on the Beaglebone Black (BBB) open source design which has a 1Ghz Sitara.. this should make the web interface of the C1 much more responsive than what is experienced with the S3 miner.
This picture shows a fully populated BBB, it's safe to assume the included BBB will be a board stripped down to the essential components to run the C1 miner.. however, if your board ever failed it would be easy to replace with a BBB.

