Vaguely relatedly: I used to design graphics accelerators for Macs (back in the 90s) we got our best performance by spending time making writing 0s (or rather solid fills) really really fast (1.5Gb/s which was lot back then) - why? because as always whatever you'd do in hardware, the software guys would piss away - for example sometimes excel would erase the background 8 times before it ever wrote a black pixel - there was little point in speeding up those black (interesting, useful) pixels when speeding up the background white ones being written over and over on top of themselves was such a win