The 510i integrated core processor has a large input/output capacity.  This article clears up how that works.   When utilizing QLAN and AES67 digital I/O over LAN A and LAN B the core has the capability to handle 256 x 256 channels as wall as 256 x 256 streams.   These digital inputs or outputs are only over the LAN A or LAN B NIC.  

  There are 8 I/O card slots on the rear of the core 510i.  These slots can handle up to 128 x 128 channels.  That brings the total I/O of the core 510i to 384 x 384 channels.   There are some caveats to keep in mind here. These cards slots have a maximum of 128 x 128. That means if you use 2 CDN64 DANTE, both set as 64 x 64 I/O, the rest of the cards slots are no longer available to pass audio.  The two DANTE cards will use all 128 x 128 channels available.  You must also remember that the CDN64 DANTE card is using the Audinate Brooklyn two chip set which limits the number of flows (or streams) to 32 x 32.    Therefore when designing your system you MUST take count of channels and streams based on the audio codec being used. 

Channel Capacity

Network Channel Capacity:   256 x 256 (in Q-SYS Core mode) / 128 x 128 (in I/O Frame mode)

Local Audio I/O Capacity:      8 audio I/O card slots - accommodates up to 128x128 total onboard I/O channels 

AEC Channel Capacity:           64 at 200ms tail length (available when configured as a Q-SYS Core Processor only)

Multitrack Player Capacity:   16 tracks, expandable to 128 tracks (available when configured as a Q-SYS Core Processor                                                           only) 

Media Drive Capacity:           Approximately 6GB on the default drive (when configured as a Q-SYS Core Processor only,                                                          upgrade options are available)