How to clear RAM?

Question

Windows

During prolonged work in a heavy program (3ds max, SolidWorks, etc.), RAM is clogged to capacity.
After the completion of the programs, the memory is not completely cleared, but about a third. The rest remains hanging, although all processes are completed.
You have to reboot your system for normal operation.
What is it and how to deal with it?
Windows 8.1

Answer 1

CCleaner