[gchadwick]

> we never prototyped in FPGAs. Most designs will not fit into a single FPGA and designs involving multiple FPGAs are a headache and the design diverges rapidly from your target due to all the overhead associated with coordinating multiple FPGAs.

It definitely depends on what you're building. When I worked on GPUs at Broadcom and CPUs at arm (and now working on OpenTitan: https://opentitan.org/) FPGAs were used. At both companies you could create a sufficiently small configuration of the design that a single FPGA was a viable target without requiring heroics for coordinating multiple FPGAs (For the GPU turn down the number of cores, for CPU I was working on the little designs A55 and such which you could fit in a sufficiently large FPGA).

Though I'd agree FPGAs aren't often used a prototyping tool. They're used for verification and often once the design is fairly mature (they're inevitably a pain to setup and use so you want to iron out all the stupid bugs first, FPGAs are most useful when you need to be running many cycles to find an issue).