Comment by MYEUHD
11 hours ago
In macOS 15 there are two metrics: "Memory used" and "Cached Files"
I'm specifically talking about "Memory used" here.
In fact, on my 16GB mac, if I open apps that use ~8GB of RAM (on top of the 5GB I mentioned earlier), it starts swapping.
When you open up Activity Monitor, to the immediate left of the "Memory Used" and "Cached Files" that you see, you'll see the Memory Pressure graph that the guy above is talking about.
On my 64 GB M1 Macbook Pro right now, I have 53.41 GB of Memory Used and 10.72 GB of Cached Files and 6.08 GB of swap, but Memory Pressure is green and extremely low. On my 8 GB M1 Macbook Air I just bought for OpenClaw, I'm at 6.94 GB Memory Used and 1.01 GB of Cached Files with 2.05 GB of Swap Used, and Memory Pressure is medium high at yellow, probably somewhere around 60-70%.
You can open up the Terminal and run the command memory_pressure to get much more detailed data on what goes into calculating memory pressure - more than just the amount of swap used, it tracks swap I/O and a bunch of page and compressor data to get a more holistic sense of what's going on and how memory starved you're going to feel in practice.
In any case - I've been absolutely mindblown at how fast my 3 8GB M1 Macbook Airs I just bought for ~$350 brand new have been - even with tons of Chrome tabs open, multiple terminal windows open, running OpenClaw and Claude Code and VS Code and doing a ton of development and testing, never once have they ever felt slow. Oftentimes they actually feel faster than my 64 GB M1 Macbook Pro, which kind of blows my mind and makes me wonder wtf is going on on my monster machine. Moreover, my M1 Macbook Pro drains battery like crazy and uses a ton of charge, whereas the Macbook Airs stay constantly below 10 watts essentially always and even with Amphetamine keeping them on 24/7, with the display off and being fully on, they'll drop to a single watt of power draw. Truly insane stuff. I've lost all my concern about RAM, to be honest (which is shocking coming from someone who bought a top of the line maxed out RAM primary machine in 2021 specifically because I felt like RAM was so important)
> I've been absolutely mindblown at how fast my 3 8GB M1 Macbook Airs I just bought for ~$350 brand new
Wait what? How did you manage that?
MacBook Air M1 was released six years ago. That’s pretty expensive for such an old machine!
1 reply →
OpenClaw found some sweet deal? /s
Yes, the person you are replying to has explained that.
The old mental model of how ram and swap works doesn't fit neatly to how modern macos manages ram. 8GB is acceptable, although on the lower end for sure.
The old mental model doesn't fit how any OS manages RAM. Every OS plays all sorts of fun guessing games about caching, predicting what resources your program will actually need etc. The OS does a lot of work to ensure that everything just hums along as best as possible.
How do you define "swapping?" Even on Intel Macs, the memory statistics don't map the way one might expect. Be careful when making assumptions about what those metrics actually mean.
I mean at that point (13 GB memory used), the "Swap used" is at several hundred megabytes.
And if I more apps (or browser tabs), the "Swap used" keeps increasing, and the "memory pressure" graph switches color from green to yellow.
The color of that graph is the indicator I'm using to know that I should close my browser tabs :p