Is it true that current Mac OS wants to use all your RAM?

Forums › Mac OS › Is it true that current Mac OS wants to use all your RAM?

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Webhead
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#3271645 14-Aug-2024 21:39

Would love to know if you are trying to figure out a problem. Would also be helpful to know what kind of machine you have (model and year).

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nongeek2025

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#3271663 15-Aug-2024 00:32

RunningMan:
Do you have an actual problem you are trying to solve?

Yes. Clarification as to what Apple is doing with users RAM:
Gist of my original questions/concerns:
1. Is it true the Mac OS will use up to all of the RAM, regardless of how much RAM there is? (Answered in general by members who agree with this claim in the article - Yes)
2. Why? (I still do not understand why Apple OS will take over all unused RAM)
3. What is it doing with all this RAM? (Also unclear to me.)

nongeek2025

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#3271664 15-Aug-2024 00:42

jarledb:
Would love to know if you are trying to figure out a problem. Would also be helpful to know what kind of machine you have (model and year).

My questions primarily relate to the article; and my observations that there has been periodic / fairly frequent significant deterioration in processing speed over the past ~5-7 years.
I wonder if the way the Mac OS is handling RAM is negatively affecting processing speed

I am currently using a 2019 MacBookPro, current OS.

RunningMan

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#3271671 15-Aug-2024 06:20

OK, it seems you don't have an actual problem with your device, just trying to understand memory allocation. This has been explained several times in different ways, as well as in the original article. Not sure tnere is any further way that people here can help in that regard.

TechSol

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#3271881 15-Aug-2024 09:53

nongeek2025:

Yes. Clarification as to what Apple is doing with users RAM:
Gist of my original questions/concerns:
1. Is it true the Mac OS will use up to all of the RAM, regardless of how much RAM there is? (Answered in general by members who agree with this claim in the article - Yes)
2. Why? (I still do not understand why Apple OS will take over all unused RAM)
3. What is it doing with all this RAM? (Also unclear to me.)

I'll chip in here.... M1 Macbook - current usage with some stuff open I have 20.65GB free from 32GB total.

So my answer is that it doesnt use all the RAM (Lowest I have seen is around 5GB free whilst doing some fairly heavy lifting)

SpartanVXL

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#3271889 15-Aug-2024 10:08

The very simple answer is, new stuff comes with new features. Some require more resources, others may not really but still run regardless.

If you trust Apple enough then there is no point worrying over it, as long as it is functioning.

It’s only when it is not functioning it becomes a problem like when windows had an issue with defender/anti-virus keeping cached memory around and blocking memory usage for normal apps. I had to use sysinternals rammap to manually clear this until it was fixed at some point.

jrdobbs

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#3271893 15-Aug-2024 10:28

timmmay:

Yeah, NAND is a lot faster than a spinning disk, but still about 10X slower than RAM.

Unless you are Linus Tech Tips and can casually spend $31K (US) on a super SSD.

Who doesn't have that sort of money to spend in the real world?

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Senecio

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#3271996 15-Aug-2024 13:20

I would be dissapointed if my OS wasn't using all of the RAM available to it. If I paid for extra RAm then I want it to be used!

Bung

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#3272067 15-Aug-2024 14:06

I found this article on MacOS memory management history interesting https://encyclopedia.pub/entry/34716. Apple had a few bandages under the hood 🤞

wellygary

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#3272069 15-Aug-2024 14:18

Senecio:

I would be dissapointed if my OS wasn't using all of the RAM available to it. If I paid for extra RAm then I want it to be used!

Especially in the case of an Apple Silicon mac, where The DRAM is physically integrated into the Processor packaging,
rather that being down the BUS somewhere....

granada29

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#3272090 15-Aug-2024 15:23

Bung:

I found this article on MacOS memory management history interesting https://encyclopedia.pub/entry/34716 . Apple had a few bandages under the hood 🤞

Interesting history but obsolete for the last 24 years. On current macOS if you are unduly concerned about memory caching (you shouldn't be) then executing sudo purge in a Terminal session will flush the cached files.

It's not recommended to do this, but it will show you a nice block of unused RAM if you feel you must.

lxsw20

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#3272092 15-Aug-2024 15:27

nongeek2025:
RunningMan:

Do you have an actual problem you are trying to solve?

Yes. Clarification as to what Apple is doing with users RAM:
Gist of my original questions/concerns:
1. Is it true the Mac OS will use up to all of the RAM, regardless of how much RAM there is? (Answered in general by members who agree with this claim in the article - Yes)
2. Why? (I still do not understand why Apple OS will take over all unused RAM)
3. What is it doing with all this RAM? (Also unclear to me.)

It's used for intelligent caching, as RAM is faster than SSD.

roobarb

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#3272190 15-Aug-2024 18:19

nongeek2025:

It didn’t use to be like that for a Mac system.

You are absolutely right, compared to an 128k Mac you have

preemptive-multitasking
virtual memory
multiple levels of caching
Rosetta
managed memory languages
the internet
multi-tabbed browsers
streaming video
harddrives, then flash drives and cloud storage
copy-on-write forking

nongeek2025:

It is not logical to me ... What’s it doing?

It's worse than that Jim, its using more memory than your system actually has! Every process is allocated 16 million terra-bytes to play with.

For example today's browsers use insane amounts of memory because every website wants to duplicate the entire library of npm in each webpage and include graphics, annoying videos and adverts. Browsers try and improve performance by caching pages you have already visited and pre-fetching sites you haven't visited.

Likewise the operating system caches applications and shared libraries in memory so it does not have to re-read the volume if the file has not changed.

gzt

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#3272194 15-Aug-2024 18:27

fairly frequent significant deterioration in processing speed over the past ~5-7 years.

Your precise mac model number might be beneficial for the discussion. There are some variations. Other than that..

You might benefit from a review of login items and default running apps on restart. Macos does a pretty good job of managing all that automatically. There are usually benefits to be gained from hand optimization if things get out of hand or the automated stuff does not really match your current focus.

freitasm

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#3272205 15-Aug-2024 19:01

nongeek2025:
RunningMan:

Do you have an actual problem you are trying to solve?

Yes. Clarification as to what Apple is doing with users RAM:
Gist of my original questions/concerns:
1. Is it true the Mac OS will use up to all of the RAM, regardless of how much RAM there is? (Answered in general by members who agree with this claim in the article - Yes)
2. Why? (I still do not understand why Apple OS will take over all unused RAM)
3. What is it doing with all this RAM? (Also unclear to me.)

Yes
Because using RAM to store pieces of data (cache) from storage is faster if any application needs that data later
Applications use RAM. More applications use more RAM. Whatever is not used by applications is used by the OS to manage the state of the machine or used as a cache to make things faster. If these applications require more RAM than is available, the OS will automatically flush the cache to make space. If there is still insufficient space, the OS will temporarily swap some RAM to storage (memory used by inactive applications will be sent to storage, freeing up some RAM for more recent applications). If multiple applications require RAM at the same time and there's not enough RAM, the OS will swap as needed, causing the system to slow down.

One way to put it simply: more RAM always results in a happy, faster system.

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