The Z3 is a floating point machine... I'd wager that it is more complex than the 4004. While the 4004 has a couple more transistors than the Z3 had relays (abou

The Z3 is a floating point machine... I'd wager that it is more complex than the 4004. While the 4004 has a couple more transistors than the Z3 had relays (about 600 in the "CPU"), the telephone relays used by the Z3 had many circuits and thus can perform more complex stuff than a single transistor in a logic circuit.