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.