If I am doing something on my computer than is quite intensive on resources (e.g. encoding videos or maybe CAD) is there a way I can tell the computer that "this single application is the only ting in the world that I care about right now so only focus on that"? Being a MacBook from a few years ago, it wasnt really built for intensive computing so it isn't very fast and I want to find a way to optimise the speeds when I need to, forgetting all of the unnecessary background processes that the computer does. Is this possible or do I just have to ensure that application is the only one running and put up with the 'background OS stuff'? Also, just out of interest, what manages the delegation of threads to different processor cores? Does the OS figure which core will handle what and try to divide it up evenly? Or is it the responsibility of whoever wrote the program to write it a certain way and use certain techniques to utilise all cores?