The keyword is CAN, there can also be huge penalties (random main-memory accesses are over a cycles typically), the parent was probably considering a regular im

The keyword is CAN, there can also be huge penalties (random main-memory accesses are over a cycles typically), the parent was probably considering a regular image transform/comparison and 20 pixels per cycle even for low resolution 100x100 images is way above what we do today. As others have mentioned, they're probably doing some kind of embedding like search primarily and then 500 cycles per face makes more sense, but it's not a full comparison.