Dump RAM contents

You don't. Trust the Operating System to be better at managing this sort of thing than you would be. If you are having problems it may be that you need more RAM.

Are you having problems?

I agree... more trouble that it's worth...

Haha, I literally came in here ready to give a bit of a speech about the nice and powerful things you can do with the /proc pseudo filesystem, only to be greeted with this.

Basically, Linux usually will try to keep stuff in memory cached such that, if you open a program again later, chances are that disk accesses to bring up the program will be minimized or eliminated altogether.

If you are seeing crashes or freezes, I can almost guarantee that something else is causing those (could be a kernel issue or a hardware issue, that's what I've seen most commonly with Linux freezing)

Temporary freezes, as opposed to crashes, are often caused by thrashing because of too little RAM (or, in Windows, some program deciding that it's going to monopolize the disk for 5 minutes).

Unfortunately, as so often, the OP provides no system specs to give us a hint. I'm assuming that he's using Linux, but even that is just an assumption.