Does adding buffer in a digital path increase the delay or reduce the delay and why?

Question

I am confused as I have seen that in some cases it increases the delay and in some cases it reduces the delay

Answer 1

There is no such thing as a "digital path" in electronics. VLSI is a connection of transistors involving analog voltage(V), current(I), and resistance(R). We have abstracted that all away from you in the form of digital hardware description languages. But in the end, a device needs to drive VIR to a collection of fanout receivers. The transistors in the driver needs to be properly sized to handle that fanout. But generally the larger the fanout, the longer the delay becomes. Adding buffers can help redistribute the fanout and improve the delay.