Do you need a RAM cleaner on Mac? How Mac memory works

How to check your Mac's memory

Open Activity Monitor from Applications › Utilities, or with Spotlight (⌘ Space), and click Memory. The list shows how much each process uses; sort it by Memory to see the biggest. The panel at the bottom shows the whole Mac:

• Physical Memory: the RAM your Mac has.
• Memory Used: everything in use right now, split into the three items below.
• App Memory: memory used by apps and their helper processes.
• Wired Memory: memory macOS itself needs, which has to stay in RAM.
• Compressed: memory of apps you aren't using, squeezed to make room. Compression is fast, and a sign macOS is managing well, not that something is wrong.
• Cached Files: files kept in otherwise unused memory so they open faster. macOS gives this memory to apps as soon as they need it.
• Swap Used: memory moved to your startup disk because RAM was full.

Memory pressure is the number that matters

The Memory Pressure graph sums all of this up, from how much is free, compressed and swapped:

• Green: your Mac has the memory it needs, however full the numbers look.
• Yellow: macOS is compressing and swapping to keep up. Fine for a while; if it stays yellow, close what you don't need.
• Red: memory has run out and macOS is relying on the disk. Apps slow down, and it's time to quit something.

A little swap is normal, even with green pressure. Swap that keeps growing to several gigabytes while you work means the Mac is short of memory for what you are doing.

What RAM cleaners actually do

A “memory cleaner” makes the free memory figure go up by emptying macOS's file cache, or by pushing apps' memory out to disk. The number looks better for a minute. Then apps read their files from disk again, more slowly, and the cache fills up again, because that is what free memory is for on a Mac.

macOS even has this built in: sudo purge in Terminal empties the file cache. Its manual describes it as a tool for performance testing with a cold cache, not a way to speed anything up. Some cleaner apps also come bundled with adware or exaggerate problems to sell a subscription; see MacKeeper's history.

“Your system has run out of application memory”

This macOS message opens the Force Quit window and lists your open apps, some of them marked as paused. It means memory and swap together ran out. To fix it:

1. Quit the apps marked as paused, or the one you can spare that you know uses a lot, such as a browser with many tabs or a virtual machine.
2. Check free disk space in System Settings › General › Storage. Swap lives on the startup disk, and a nearly full disk is a common cause of this message; see how to free up disk space.
3. If one app's memory keeps growing for hours, even when idle, it has a memory leak. Update it, or restart it once a day until the developer fixes it.
4. Restart your Mac if the message keeps coming back.

What actually frees memory

• Quit apps you aren't using. On a Mac, closing an app's last window often leaves the app running.
• Close browser tabs you don't need, and remove extensions you don't use. Each tab is a separate process with its own memory.
• Turn off login items and background helpers you don't need in System Settings › General › Login Items & Extensions.
• Restart now and then. It ends helpers that have been running for weeks and clears swap.

For more ways to make a slow Mac faster, see how to speed up a slow Mac.

How much memory does a Mac need?

Enough that memory pressure stays green with the apps you normally use. For web, mail and office work, 8 GB is usually enough, and 16 GB leaves room for many tabs and apps at once. Photo and video editing, development and virtual machines want 16 GB or more.

On a Mac with Apple silicon, memory is part of the chip and can't be added later. If memory pressure is often yellow or red with only your usual apps, the fix is a Mac with more memory, so buy for the work you expect to do in a few years.

Mac memory in Tidy My Mac

• Performance shows live memory with macOS's own pressure verdict, splits your RAM the way Activity Monitor does, and lists apps with their helpers counted in. It warns when one app holds a quarter of your memory or swap grows large. It has no “free up RAM” button, on purpose.
• Startup Items and Background Services show everything that starts with your Mac and keeps using memory, with the app it belongs to.