There are many ways to create adders [0]. And other circuits for that matter. If you are willing to expend more transistors, you can decrease the propagation de

There are many ways to create adders [0]. And other circuits for that matter. If you are willing to expend more transistors, you can decrease the propagation delay [1], that is, the delay until all outputs have settled to a stable value. Basically the propagation delay is the "longest path" from any input to any output and is a constraint on how fast the clock can go without messing up the calculations. Other ways to make a CPU faster, which costs transistors, is improved branch prediction and parallelism (modern CPUs execute a lot in parallel, even single cores. If there is a conditional branch and it guessed wrong, it has to flush all the wrong stuff it calculated. But there are still speed gains if the branch prediction is okay.) [0] https://en.wikipedia.org/wiki/Adder_(electronics) https://en.wikipedia.org/wiki/Adder_(electronics) [1] https://en.wikipedia.org/wiki/Propagation_delay https://en.wikipedia.org/wiki/Propagation_delay