Are there many individual components of the Xnn series of algos which won't fit on an arria or even a cyclone ?
Yes. Some of the components hardly fit on a 9P. The cubehash example i gave a few posts ago.
Are you saying the algorithm for an individual cubehash pipeline hardly fits on a 9P???... while I havent studied cubehash specifically, its claimed to take 200 cycle on a basic CPU, and I can implement a lot of basic CPU cores on a 9P...
A pipeline, sure, lots of pipelines, if you want to unroll it fully and obtain real (1Gh/s+) performance it would take the entire 9P and it's not clear that a fully unrolled version of it would fit at all.