18.26. What is the maximum number of processors supported by Symphony OCR before a performance limit/wall will be hit because of application bitness?

If your license allows for our maximum core count of 16.  This is 16 cores used for OCR itself, and we'll use another 8 cores for pre-analysis.  Pre-analysis takes 1/50th the time as OCR, so it's only important to have 16 dedicated physical cores if you are trying to maximize Symphony performance.

Application bit-ness has no influence on our performance for multi-core operation, so no performance degredation from that as you add cores.

What's more likely is that Symphony will eventually saturate the bandwidth available for transferring files (either b/c of limitations at via your internet connection, or the server bandwidth).  Other potential limiting factors would be free RAM and disk performance (but on any modern server, these are negligible compared to internet bandwidth).