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Comment by thebean11 | Hacker News Reader

16GB of RAM seems so low in 2021. OTOH, hard drives are so fast on these things that maybe 16 is good enough with the SSD as overflow.

I ended up shelling out the extra $400 for 32GB, but didn't feel great about it!

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I've heard from people with M1 laptops that they perform surprisingly better than Intel laptops with less RAM (on the Mac). I imagine the same will hold with the Pro and Max, although it will depend a lot on what type of work you're doing.

I am one of those people. I bought an 8gb M1 Air last month for a project (while I waited for the new models to be released). It baffles me how well this little computer performs with less RAM than I've had in a computer since 2009. I'd love an explanation of how that works. Maybe the SSD is so fast that swapping isn't a big deal?

I looked into this angle recently. The SSDs in the new MBPs are roughly 3x as fast as the one in my 2015 MBP (7.4GB/s vs 2GB/s). To contextualize, the new MBPs have roughly half as much SSD bandwidth as my MBP does memory bandwidth.

Which is to say the SSD is much closer to being as fast as RAM, which would explain why is subjectively can make better use of less memory.

Neat!

It’s also possible that they’re using more and better tricks from iOS to handle memory - in which case the Intel Macs might show similar results if given similar speed disks

What kind of tricks?

I have m1 air with 8Gb and I see that had to take 16Gb at least. Not sure about 32GB, but 16 is the minimum. Profile: JS, TS, Rust, sometimes Java.

On the other hand I've been running 16GB of ram for a while and I can't conceive of a reason why I would need more. 32GB seems like overkill. What would you do with all of that ram? Open more tabs?

Compilation, graphics work, heavy-weight IDEs

And, if you're spinning on 16GB ram on an M1, you might be eating through the SSD powering your swap space and not know it.

indeed. From my experience, I see that my MBA uses swap sometimes, but I can't notice it. Still, I want to avoid it.

Looking at activity monitor, I'm currently using ~19GB, doing nothing special (IntelliJ, 15 chrome tabs, Spotify, Slack). Docker Desktop was using 8GB before I killed it. And this is on an Intel Mac so it doesn't include GPU memory usage I believe, which is shared in M1 Macs.

This likely isn't a perfect metric, if I were closer to the limit I think MacOS would get more aggressive about compression and offloading stuff to disk but still.

Browsers generally allocate RAM with abandon but any one process is not necessarily memory bound. It just means that they are using that as page cache.

Bah IntelliJ is a pig. It's worth it, but it's a pig.

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