For arguments sake, when it comes to battery, quad core is a lot better, because power grows with the square of speed, so quad core can run at a quarter of the speed for a total power reduction of a factor 4. Overhead for managing multiple threads is negligible.
Yes and four women can deliver one baby in nine months by eating a quarter of the food for a total food consumption reduction of a factor 4.
As of next Tuesday, C will be flushed in favor of COBOL. Please update your programs.