Is there a limit anywhere to the maximum number of video cards in a 64-bit linux install, if being used only for OpenCL?
Creative use of some PCI-e riser with bridges on them would allow 20-32 cards in a single system, which would be really really handy for a project. Ignoring the mechanical, power and heat issues, is there anything software wise that would prevent this from working?
I don't know about the exact limit, but there seems to be a limit. I've found this page a while ago when doing some research on GPU computing: http://fastra2.ua.ac.be/?page_id=214
This is about some technical details of the FASTRA II "personal" supercomputer that has been build at the University of Antwerpen. They are using Nvidia Geforce cards but the BIOS issue they had to deal with should be independent of that fact.