understanding memory in activity monitor

Hi all,

Sorry for a very non tech question. . .I have a 2013 Macbook Pro, 8 gig os -x 10.9.5, running Maverick -- the activity monitor isn't very clear to me, the old pie chart would have better for me to understand how much memory I have. I work with iMovie & GIMP quite a bit, so I have a lot of pic files & movie clips, I'm thinking I should move the clips & photos off the Mac into ext drive or whatever, so I don't use too much memory in the Mac. thanks for any info about this!
I don't think I can add more memory to this computer, from what I recall when I got it.
By the way, it seems to be running fine, and the activity monitor shows a low green line for pressure. I just don't know where to find out how much memory is being taken up by files, and how much is available, in a general sense. (why the pie chart would have been easier for me).

Jan H.

You didn't give us enough information to know about your memory limits. Open "About This Mac" from the Apple icon upper left corner and tell us what it says about your Mac there. As for the other questions, there is a fundamental difference between memory and storage. When you talk about files and clips of movies, those take up storage on the HD, but not what is called memory. Memory is the RAM that the OS uses when it is running, and is zeroed out when you power off. So moving files doesn't affect MEMORY, but does STORAGE. How big is your HD and how much space does it have left?

As for Memory, OS X does a pretty good job managing it for you. If the pressure is low, don't worry too much about it. IF you are really curious, on the Memory tab in Activity Monitor, click on the column heading labelled "Memory" until the biggest user is at the top. Most of the time it's kernel_task or SystemUIServer, both system components.

EDIT: Another key factor in Activity Monitor is how much is listed under "Swap Used:" on the Memory page. The optimum is to keep it at zero.

Hi Jan:

It won't matter if your Movie and GIMP files are on an external hard drive or the built in SSD, the programs are going to use the same amount of system memory. Now, if you're referring to SSD space as memory (incorrect terminology) then moving the Movie and GIMP files to the external hard drive will preserve space on the SSD. You really didn't provide us with specs for your 2013 MacBook Pro, but those models have fixed system memory and SSDs. Referring to available space, the Activity Monitor is of no use but is useful for determining how much memory certain apps are using when running.

You are confusing memory with storage. The files stored on your HDD are going to affect how much storage you have. So open up Disk Utility and highlight Macintosh HD and look at the bottom to see how much Available space you have. You should ideally leave at least 20% of your Capacity to ensure proper operation of OS X.

Now to the memory question, I'll answer this in the context of my machine, so the numbers won't match yours, but you'll understand how it works. I have the following numbers:

What you care most about is the Memory used section and of that the Wired section. In my case I've used a good portion of memory, and nearly 4GB is wired meaning that it can't be moved around because of its use by applications. Looks like my memory needs have been greater than what has been available with the applications that are running and thus I've used some swap space to make memory available to applications..

The pressure meter is just a representation of where your needs are. That is, if you have many applications holding onto a lot of memory (Wired) and making further demands, then your memory pressure would be high and assuming you can upgrade your memory higher, this would help alleviate the situation. But, like me, if you are on a Retina MBP that has fixed memory, then you have what you have..