Flowers said the Bletchley Park code breakers could hardly believe their eyes when they saw Colossus for the first time. Operating at 5,000 characters per second, it was soon analyzing over 100 messages a week. Not content to leave things there, Flowers used parallel processing in the Mark II Colossi to push up the speed to an incredible 25,000 characters per second
It would compute much faster than humans could ever do