Super Brain: Too expensive and too unefficient
Got 208 Millions of USD left? Buy yourself a second brain. World`s fastest computer is fairly as capable as your own head. But there is one downside. It needs the electricity of 1200 households to run. Or in other words: 100.000 times more energy than your own brain. Not really efficient. There might be one upside, however: It will never complain about headache (Not meaning to have sex with it…nooooo).