Complex sentence: For comparison, later stored-program computers such as the Manchester Mark 1 of 1949 used 4050 valves, while ENIAC (1946) used 17,468 valves.
Split into simpler sentences: For comparison, later stored-program computers such as the Manchester Mark 1 of 1949 used 4050 valves. In comparison, ENIAC (1946) used 17,468 valves.