FPGAs are dedicated processors known for doing two things: very fast processing, and being reprogrammable. CPUs have to be general-purpose processors that run an OS, but an FPGA has the luxury of doing a dedicated task, so the architecture is different.
The problem is that while FPGAs are reprogrammable to do new, specific tasks, they aren’t that easy to program. In fact, it’s often pretty hard to do. That’s Accelize’s sales pitch. Rather than writing the code to reprogram the FPGAs in your servers, it has the templates for you.