Hardware is fast enough when it can run your software fast enough to do what you want. :) Approximately all software in the world is very suboptimal, as is occ

Hardware is fast enough when it can run your software fast enough to do what you want. :) Approximately all software in the world is very suboptimal, as is occasionally proven by people who make things go fast on slow hardware for fun and games (eg see 3d engines on c64 or realtime video decoding & streaming from floppy on 8088)