Asynchronous circuits is faster than synchronous circuits .
Synchronization means less chance of hazards but synchronous circuit can increase the delay. So, synchronous circuits cannot have faster operation than asynchronous one ..
In asynchronous circuits, there is no clock, and the state of the circuit changes as soon as the input changes. Since they don't have to wait for a clock pulse to begin processing inputs, asynchronous circuits can be faster than synchronous circuits .