Optimize Ram will free up physical ram used on your computer. To erase memory, use total amount of memory installed in the computer. When using all available memory when clearing memory, open applications can be slow to open after it's finished since the memory has been completely erased. You will get better performance and avoiding problems when freeing up more ram that will be made available for new applications and other processes.

Several things could cause the operating system not to manage the available memory as optimized as possible, such as very large programs, program crashes, memory holes, a lot of background programs etc.