There are two things you should consider here, wall clock time, and cpu time. Making code faster using multiple threads will increase CPU time by some amount, b

There are two things you should consider here, wall clock time, and cpu time. Making code faster using multiple threads will increase CPU time by some amount, but because that work is now distributed between several cores it should actually reduce wall clock time. There are many CPU bound tasks which can be made multithreaded and faster, but it does depend on the task and how much extra coordination you’re adding to make it multithreaded.