RAM Limits ME

[orionquest]

This horse has been beaten enough, going down this Ad nauseam of a rabbit hole, it depends on the workload!

Even the OP doesn't understand this in their opening statement, alluding to some IT knowledge and leaving out the what is being done with the machines with 8gigs.

Every user could benefit with more RAM, either it be for change of tasks/workloads, software resource creep, longer term flexibility, and since AS memory is shared with GPU give more resources to apps.

I run an old haswell system, yes 9 years old, but with 32 gigs. Glad I purchased it this way because my usage has changed 3 times. Floating between, photography, web programming, video/motion graphics, and dabbling with data analytics. It still crunches everything I throw at it with multiple apps open. I doubt I could do this well on a 8 gig system.

 

[pshufd]

I have a 2008 Dell XPS Studio with 48 GB of RAM. It's actually fine for office work but I haven't used it in a year or two. I also have a custom i7-10700 desktop with 128 GB of RAM. Great for running virtual machines.

The sweet spot for me is 32 GB on Apple Silicon Macs. I bought an M1 mini with 16 and quickly found out it wasn't enough but there were no other options at the time. I have an M1 Max Studio and M1 Pro MacBook Pro with 32 GB of RAM and those two systems are good enough. I can't run all of my stuff on any Mac at the same time but I have several Macs that I can run together to be able to run everything at the same time.

macOS is adding more and more services with time and these chew up RAM and CPU.

I had a look through the Costco catalog and was surprised that all of the premium laptops came with 32 GB of RAM. Their cheaper laptops came with 16. They are all also a tier above on storage compared to Apple. I'd say that 16 should be base and 32 for premium.

The M1 Macs with 8 GB should be fine for most users. Not optimal but it should work. My wife has a 2018 base mini and she's fine with it. I offer her an upgrade annually and she's happy with what she has.

 

[meson]

Hi! I am lifelong Windows user, since I started working at IBM (eons ago in 1984!) I grew up with the technology: Mag card typewriter->8” floppy->5”floppy->”Tiger (orange) terminal split in 4->Big head monitor green screen (one color!!!)-> 256gb Laptop that took FOREVER to boot up and then it feels like the technology just took OFF from there, it’s really amazing and was always Windows, for me.

I am longtime IPhone, IPAD, Apple watch, Airpods user, see a trend here?? I decided it’s time to pull the trigger and switch, so I bought a Macbook 15” Air. I am, like you, not doing any crazy computations. Usage determines how much storage/RAM one really needs, still, I found it hard to determine prior to purchase. And, I did a lot of research! A friend of mine who is lifelong Apple user assured me 8gb RAM would be enough, with which I agreed.

So I was alarmed to see my 8gb RAM chewed up to almost 6.5gb when I checked Activity Monitor!!! Beyond the apps I recognize, there’s so much stuff in there I don’t know! I rebooted, it went down a bit, jumped back up, so it seems I run around 6-6.5gb usage. My questions/concerns:

1. I’m not running out of space, but, obviously, if I things slow down and apps crash or buffer, I’m exceeding my RAM!
2. I feel like I can’t install much more than I have and I’ve hardly installed ANYTHING! Hopefully, I won’t need much more……..
3. What apps can I shut down? I know how to Quit an app, but it comes right back! How can I permanently shut down an app I don’t need?
4. How do I know which ones I don’t need??
5. What else can I do to minimize RAM usage?
6. Ultimately, I think, I will have to trade in for a 16GB machine if it doesn’t work out, but, of course, I don’t want to do that. I’m really disappointed that I just didn’t get 16gb RAM! Every thing I read online said M2 is soooo much more efficient. But I feel like I may have made a mistake : (
7. Thank you!! Donna

MacOS uses ram as a cache. It will load a bunch of stuff during boot to get the system up and running. Once you are running, it will begin caching things in ram that it anticipates you may need based on your normal usage. It doesn’t release things in ram until it needs to. The idea is that anything sitting in ram that is not needed isn’t harming anything, just like that novel on the bookshelf you may never read again and dispose of when you need to reclaim shelf space. It doesn’t matter whether you have 8GB or a 2019 MacPro with 1.5TB of ram, MacOS will use and cache what it can in ram.

As long as your daily use is not running virtual machines, editing massive photos or large batches of photos, editing large video files, or something else that is very ram intensive, you will be fine. Even if you push things a bit and the machine starts swapping, the SSD is very fast and you may not even notice.

A better indicator to look at in Activity Monitor is the memory pressure. When it is red, your machine is at the point where it is swapping regularly and using the built in storage as ram. When it is green all is good. When it is yellow, it is fine as well, but it is an indication that you have just the right amount of ram for your current usage and will start swapping heavily if you push the ram needs further.

As a long time computer user, you can always revert to old habits of closing down anything that is not needed. That said, the vast majority of processes that show up in activity monitor are background processes and daemons meant to make many newer features in MacOS run smoothly. It drives me nuts that the OS uses so many resources, but it is what it is with modern OSes.

 

[dmt43]

MacOS uses ram as a cache. It will load a bunch of stuff during boot to get the system up and running. Once you are running, it will begin caching things in ram that it anticipates you may need based on your normal usage. It doesn’t release things in ram until it needs to. The idea is that anything sitting in ram that is not needed isn’t harming anything, just like that novel on the bookshelf you may never read again and dispose of when you need to reclaim shelf space. It doesn’t matter whether you have 8GB or a 2019 MacPro with 1.5TB of ram, MacOS will use and cache what it can in ram.

As long as your daily use is not running virtual machines, editing massive photos or large batches of photos, editing large video files, or something else that is very ram intensive, you will be fine. Even if you push things a bit and the machine starts swapping, the SSD is very fast and you may not even notice.

A better indicator to look at in Activity Monitor is the memory pressure. When it is red, your machine is at the point where it is swapping regularly and using the built in storage as ram. When it is green all is good. When it is yellow, it is fine as well, but it is an indication that you have just the right amount of ram for your current usage and will start swapping heavily if you push the ram needs further.

As a long time computer user, you can always revert to old habits of closing down anything that is not needed. That said, the vast majority of processes that show up in activity monitor are background processes and daemons meant to make many newer features in MacOS run smoothly. It drives me nuts that the OS uses so many resources, but it is what it is with modern OSes.

Thanks this helps a lot! I will keep an eye on memory pressure. My daily use is not: running virtual machines, editing massive photos or large batches of photos, etc. I will see how it goes with my usage.

 

[mr_roboto]

I am longtime IPhone, IPAD, Apple watch, Airpods user, see a trend here?? I decided it’s time to pull the trigger and switch, so I bought a Macbook 15” Air. I am, like you, not doing any crazy computations. Usage determines how much storage/RAM one really needs, still, I found it hard to determine prior to purchase. And, I did a lot of research! A friend of mine who is lifelong Apple user assured me 8gb RAM would be enough, with which I agreed.

So I was alarmed to see my 8gb RAM chewed up to almost 6.5gb when I checked Activity Monitor!!! Beyond the apps I recognize, there’s so much stuff in there I don’t know! I rebooted, it went down a bit, jumped back up, so it seems I run around 6-6.5gb usage. My questions/concerns:

1. I’m not running out of space, but, obviously, if I things slow down and apps crash or buffer, I’m exceeding my RAM!
2. I feel like I can’t install much more than I have and I’ve hardly installed ANYTHING! Hopefully, I won’t need much more……..
3. What apps can I shut down? I know how to Quit an app, but it comes right back! How can I permanently shut down an app I don’t need?
4. How do I know which ones I don’t need??
5. What else can I do to minimize RAM usage?
6. Ultimately, I think, I will have to trade in for a 16GB machine if it doesn’t work out, but, of course, I don’t want to do that. I’m really disappointed that I just didn’t get 16gb RAM! Every thing I read online said M2 is soooo much more efficient. But I feel like I may have made a mistake : (
7. Thank you!! Donna

EDIT: Beaten to essentially all the same points by @meson !

re: #1, macOS automatically uses RAM as disk cache. Just booting the computer will read enough from disk to fill up a lot of RAM with cached data. But this isn't a real problem since macOS deallocates disk cache as needed to free up RAM for other purposes.

For this reason, it's a lot better to use Apple's "memory pressure" graph to get an idea of how out of memory you are. Low / green memory pressure means you're good, medium / yellow memory pressure means there may be some swapping and you might want to quit an app (just pick one you're not using right now which is using lots of memory), and red / high means the system is swapping a lot and losing performance and you really need to quit some things.

re: #2 through #4, what do you mean "it comes right back"? Quitting an app should quit it. Also, installing most apps won't use any RAM until you run the app - don't worry uninstalling software. (There are exceptions, apps that start up background services which might always be using some RAM, but those aren't common.)


Overall, what are you doing with the computer? If it isn't too intense, and especially if you don't use more than a web browser and one other app actively, you won't have real problems with 8GB.

 

[dmt43]

EDIT: Beaten to essentially all the same points by @meson !

re: #1, macOS automatically uses RAM as disk cache. Just booting the computer will read enough from disk to fill up a lot of RAM with cached data. But this isn't a real problem since macOS deallocates disk cache as needed to free up RAM for other purposes.

For this reason, it's a lot better to use Apple's "memory pressure" graph to get an idea of how out of memory you are. Low / green memory pressure means you're good, medium / yellow memory pressure means there may be some swapping and you might want to quit an app (just pick one you're not using right now which is using lots of memory), and red / high means the system is swapping a lot and losing performance and you really need to quit some things.

re: #2 through #4, what do you mean "it comes right back"? Quitting an app should quit it. Also, installing most apps won't use any RAM until you run the app - don't worry uninstalling software. (There are exceptions, apps that start up background services which might always be using some RAM, but those aren't common.)


Overall, what are you doing with the computer? If it isn't too intense, and especially if you don't use more than a web browser and one other app actively, you won't have real problems with 8GB.

#1 Thank you for explaining how the RAM works.

#2-4 As an example, I quit Microsoft Sharepoint - didn’t know why it even running, UNLESS an MS365 app was using it. Anyway, it was using about 26GB RAM so I quit and then I noticed it came back. It may have been after I rebooted (I don’t recall), which is going to be the case, isn’t it? Every time I boot, any app I quit will come back, which is why I asked how you one may permanently shut down an app/service.

My usage is not intense: mostly MS365 apps, Web browsing (I use my Ipad mostly), maybe some stuff with photos, but nothing major. It should be fine. What worried me was seeing 6.5GB+ out of 8GB RAM used when I knew my usage was light! But, back to #1 + other answers here, I think that explains it! thanks everyone, it’s all very helpful ; )

 

[fakestrawberryflavor]

always get as much ram as you can. No reason to get half the amount to save ~$200 or whatever, especially if you decide that extra cost over the life time of the machine. Just dollars or cents per day, depending.

 

[ArkSingularity]

Yea, Mac OS is very aggressive about keeping stuff in cache until it actually needs to purge it. I found out recently that the kernel will often even compress some speculatively loaded memory mapped file pages (pages that were cached from file reads) because it's much faster to simply decompress them from memory than it is to go grab them from the disk in the event that they are needed again. It makes sense, if there is space for it and the system isn't having to page out any data it deems to be "actively used", it may as well make the most use out of its memory that it can.

Frankly I'm wowed at how far these things can be pushed before performance problems actually become noticeable. I recently tried to bring my 16GB Mac to its breaking point, and was pretty much unable to do so with the workflows I normally use. To give you an idea:

* Created a VM and assigned 16GB of RAM to it (yes, QEMU lets you do this), opening every single app installed within the VM, and ran YouTube with software decoding and let it play (uses plenty of CPU to do this at max resolutions).
* Simultaneously opening full software development workflows on MacOS that require 10+GB of RAM on their own. Didn't break a sweat.
* Opened up a full 96khz Logic Pro project, at the same time, and let it play (no hiccups, and that's with third party plugins and everything).
* Opened Cities Skylines (a game that can easily use 15GB of RAM on its own), and it loaded right up in normal time without any noticeable problems. (I thought that this would for sure cause the computer to slow down noticeably, but even in addition to everything else, it ran perfectly fine. Frame rates were normal.)
* Threw Minecraft on top of it, for good measure, thinking that for sure running two games at the same time at max settings would bring this thing to its knees. Nope, both maintained good framerates and chugged right along.

YouTube was still playing through software decoding right within the VM, Logic Pro was still playing the project without hiccups, both games were still running and getting good framerates at the same time, and none of my 20+ browser tabs had to be reloaded. The rest of my development workflows were snappy, memory pressure was still only in the yellow (never dipped into the red once), and the only indication I had that I had just pushed this computer this hard was the fact that it was quite warm on the bottom and new apps took 2-3 seconds to launch rather than being near-instant.

To be fair, there absolutely ARE plenty of workloads that can stress 16GB of RAM to the point of bringing the memory pressure into the red (plenty have managed to do it), but I have yet to find a workload myself that will do it. These systems can handle quite a bit more than their Windows counterparts can.

 

[pshufd]

Yea, Mac OS is very aggressive about keeping stuff in cache until it actually needs to purge it. I found out recently that the kernel will often even compress some speculatively loaded memory mapped file pages (pages that were cached from file reads) because it's much faster to simply decompress them from memory than it is to go grab them from the disk in the event that they are needed again. It makes sense, if there is space for it and the system isn't having to page out any data it deems to be "actively used", it may as well make the most use out of its memory that it can.

Frankly I'm wowed at how far these things can be pushed before performance problems actually become noticeable. I recently tried to bring my 16GB Mac to its breaking point, and was pretty much unable to do so with the workflows I normally use. To give you an idea:

* Created a VM and assigned 16GB of RAM to it (yes, QEMU lets you do this), opening every single app installed within the VM, and ran YouTube with software decoding and let it play (uses plenty of CPU to do this at max resolutions).
* Simultaneously opening full software development workflows on MacOS that require 10+GB of RAM on their own. Didn't break a sweat.
* Opened up a full 96khz Logic Pro project, at the same time, and let it play (no hiccups, and that's with third party plugins and everything).
* Opened Cities Skylines (a game that can easily use 15GB of RAM on its own), and it loaded right up in normal time without any noticeable problems. (I thought that this would for sure cause the computer to slow down noticeably, but even in addition to everything else, it ran perfectly fine. Frame rates were normal.)
* Threw Minecraft on top of it, for good measure, thinking that for sure running two games at the same time at max settings would bring this thing to its knees. Nope, both maintained good framerates and chugged right along.

YouTube was still playing through software decoding right within the VM, Logic Pro was still playing the project without hiccups, both games were still running and getting good framerates at the same time, and none of my 20+ browser tabs had to be reloaded. The rest of my development workflows were snappy, memory pressure was still only in the yellow (never dipped into the red once), and the only indication I had that I had just pushed this computer this hard was the fact that it was quite warm on the bottom and new apps took 2-3 seconds to launch rather than being near-instant.

To be fair, there absolutely ARE plenty of workloads that can stress 16GB of RAM to the point of bringing the memory pressure into the red (plenty have managed to do it), but I have yet to find a workload myself that will do it. These systems can handle quite a bit more than their Windows counterparts can.

Something that can stress small memory Macs is running several large programs that need to run Rosetta 2, particularly with WINE, or under another interpreter like Java.

Monterey had a moderate number of memory leak problems, particularly with external monitors that were fixed after a couple of updates. I had to reboot my M1 Pro MacBook Pro daily to clear up RAM usage for a month.

 

[ArkSingularity]

Something that can stress small memory Macs is running several large programs that need to run Rosetta 2, particularly with WINE, or under another interpreter like Java.

Monterey had a moderate number of memory leak problems, particularly with external monitors that were fixed after a couple of updates. I had to reboot my M1 Pro MacBook Pro daily to clear up RAM usage for a month.

Yea, I remember those memory leak issues. I'm glad that seems to have improved, I had several occasions of things deciding to use 20GB+ of memory for no reason.

I still have not upgraded from Monterey on my 2020 M1 just out of fear that Ventura would introduce new issues. Ventura is working fine on my 14", so maybe I should go ahead and take the jump. But I figure it doesn't make sense to rock the boat if the dust seems to have settled.

 

[pshufd]

Yea, I remember those memory leak issues. I'm glad that seems to have improved, I had several occasions of things deciding to use 20GB+ of memory for no reason.

I still have not upgraded from Monterey on my 2020 M1 just out of fear that Ventura would introduce new issues. Ventura is working fine on my 14", so maybe I should go ahead and take the jump. But I figure it doesn't make sense to rock the boat if the dust seems to have settled.

One of the programs that I used was broken by one of the Ventura updates and the vendor had to release a new version to get it to work. It took about a week and I was unhappy with the downtime to restore from Time Machine. Ventura has been less stable than I like which is why I have a Mac for testing and test out new macOS versions before updating my production systems.

 

[ArkSingularity]

One of the programs that I used was broken by one of the Ventura updates and the vendor had to release a new version to get it to work. It took about a week and I was unhappy with the downtime to restore from Time Machine. Ventura has been less stable than I like which is why I have a Mac for testing and test out new macOS versions before updating my production systems.

Yea, that's been my concern as well. XCode especially has a tendency to have a few hiccups on upgrades, I had to deal with some of them when I made the upgrade from Big Sur to Monterey.

I actually don't mind Monterey. It was a heaping mess when it first came out, but I've had very few problems with it in more recent times. I'm still having to get used to all of the changes (the new settings layout especially) in Ventura, and haven't really gotten a good sense of where everything is yet.

 

[pshufd]

Yea, that's been my concern as well. XCode especially has a tendency to have a few hiccups on upgrades, I had to deal with some of them when I made the upgrade from Big Sur to Monterey.

I actually don't mind Monterey. It was a heaping mess when it first came out, but I've had very few problems with it in more recent times. I'm still having to get used to all of the changes (the new settings layout especially) in Ventura, and haven't really gotten a good sense of where everything is yet.

I upgraded to Ventura for improved hypervisor support, and the weather and clock apps. I used to run a Windows 10 virtual machine just to get their weather program. What's amusing is that Microsoft got rid of the weather app in Windows 11 and Apple added it in Ventura.

I also downgraded one of my older Macs to Big Sur from Monterey as something in the June release broke WiFi for me. The system would run on WiFi for 10-15 minutes and then it wouldn't work. I would have to reboot to get it working again. I've seen a few reports of this on Reddit and downgrading to Big Sur solved this particular problem. I do not see it with Ventura but that Mac can't natively run Ventura.

You kind of have to choose the operating system based on your hardware and the bugs for particular versions of macOS. I am hoping that they fix the WiFi bug so I can go back to Monterey.

 

[TechnoMonk]

Hi! I am lifelong Windows user, since I started working at IBM (eons ago in 1984!) I grew up with the technology: Mag card typewriter->8” floppy->5”floppy->”Tiger (orange) terminal split in 4->Big head monitor green screen (one color!!!)-> 256gb Laptop that took FOREVER to boot up and then it feels like the technology just took OFF from there, it’s really amazing and was always Windows, for me.

I am longtime IPhone, IPAD, Apple watch, Airpods user, see a trend here?? I decided it’s time to pull the trigger and switch, so I bought a Macbook 15” Air. I am, like you, not doing any crazy computations. Usage determines how much storage/RAM one really needs, still, I found it hard to determine prior to purchase. And, I did a lot of research! A friend of mine who is lifelong Apple user assured me 8gb RAM would be enough, with which I agreed.

So I was alarmed to see my 8gb RAM chewed up to almost 6.5gb when I checked Activity Monitor!!! Beyond the apps I recognize, there’s so much stuff in there I don’t know! I rebooted, it went down a bit, jumped back up, so it seems I run around 6-6.5gb usage. My questions/concerns:

1. I’m not running out of space, but, obviously, if I things slow down and apps crash or buffer, I’m exceeding my RAM!
2. I feel like I can’t install much more than I have and I’ve hardly installed ANYTHING! Hopefully, I won’t need much more……..
3. What apps can I shut down? I know how to Quit an app, but it comes right back! How can I permanently shut down an app I don’t need?
4. How do I know which ones I don’t need??
5. What else can I do to minimize RAM usage?
6. Ultimately, I think, I will have to trade in for a 16GB machine if it doesn’t work out, but, of course, I don’t want to do that. I’m really disappointed that I just didn’t get 16gb RAM! Every thing I read online said M2 is soooo much more efficient. But I feel like I may have made a mistake : (
7. Thank you!! Donna

Stop worrying about how much usage it shows. what is the memory pressure? red/yellow or green?

I use a 64 GB M1 Max, it shows around 50+ gigs marked for use. My MBA M2 8 GB shows 5-6 GB used. I would be concerned if the memory pressure is consistently red or yellow. Are Apps crashing, if so? which ones?

 

[richmlow]

Generally speaking, it makes sense that Apple is using Apple Silicon CPUs in all of its computing platforms (mobile, laptop, desktop). Over time, the CPU designs iterate and are applied like clockwork.

However, I can't help but think that Apple is painting itself into a corner when it comes to SoC on its desktop machines. Currently, Apple Silicon CPUs do not seem to scale very well. That's why we get M1, M2 (and their variants) by "doubling and gluing" smaller chips together.

Personally, I need massive amounts of RAM and a modest number of cores (say 10). For my workflow, GPU cores have very little effect.


richmlow

 

[theorist9]

re: #2 through #4, what do you mean "it comes right back"? Quitting an app should quit it.

I'm not precisely clear on how launchd works—whether (with a specific configuration) it keeps apps from quitting, or immediately relaunches them upon quitting. But either way, this could cause an app to appear to "come right back" after you try to quit it. For instance, when I force-quit GlobalProtect in Activity Monitor, it either quits and instantly reappears, or doesn't quit at all (I can't tell):

How to quit GlobalProtect (mac)

If you've used the globalprotect client for Mac, you may notice that there is no way to exit it, meaning it can continue submitting information about your system to your company in the background, including your current patches, interface information and much much more, even at times you're not...

joshcurry.co.uk

 

[wegster]

I have a base M1 Max Studio and I run production and a Windows virtual machine and it fits in 32 GB of RAM. Next to it I have a 2015 iMac 27 with 32 GB of RAM and it runs my office stuff. There's typically 10 GB of RAM free on the iMac so I'm using up about 22 GB of RAM for macOS, programs and cache. I bought the iMac for $200 6 weeks ago, mainly for the display, but having all of the RAM is nice. It can hold 64 GB of RAM but 16 GB DIMMs for that particular system are very expensive. If I wanted more RAM, I'd look at 2017, 2019 and 2020 iMacs.

I also have an M1 mini that was replaced by the iMac. I'm not sure what to do with it.

My 2021 MacBook Pro 16 has 32 GB of RAM. I can run production + office, Windows + office on it but not all 3 at the same time without swapping. I'd say that 48 GB of RAM would be perfect for me on a laptop. 64 works nicely on the desktop on multiple Macs.

So if you need more RAM for programs that aren't CPU-intensive, a used iMac may be far more cost-efficient than adding RAM to an Apple Silicon Mac.

Be careful on assumptions on this. macOS and Linux/Unix does a lot of caching which isn't really 'actively used or required' for the filesystem, as well as caching things like libraries used by 1 or more programs. It's a bit confusing, but until the point you're seeing significant use of swap space (using disk like RAM), and numerous page in/page outs, you're fine. You can see the app/wired/compressed in activity monitor, and in other tools like iStats:

This is actually relatively idle at the moment on my system, and has zero issues running the same apps on my MBP16 32GB, but note it's claiming 46GB of app memory, 12GB of which is caching, and wired (can not be pushed out of actual RAM) is 3.4GB. 'Pressure' is a bit ambiguous, but a reasonable summary - until you're at 70% or higher there regularly, I just wouldn't worry about it much/you're OK.

 

[pshufd]

Be careful on assumptions on this. macOS and Linux/Unix does a lot of caching which isn't really 'actively used or required' for the filesystem, as well as caching things like libraries used by 1 or more programs. It's a bit confusing, but until the point you're seeing significant use of swap space (using disk like RAM), and numerous page in/page outs, you're fine. You can see the app/wired/compressed in activity monitor, and in other tools like iStats:
View attachment 2246614

I prefer swap to be zero. There are lots of ways to do that inexpensively these days. I picked up a 2015 iMac with 32 GB of RAM for $200 and run stuff on that system that use up RAM but have modest CPU requirements. That's a lot cheaper than going up a RAM tier with Apple Silicon.

 

[wegster]

I prefer swap to be zero. There are lots of ways to do that inexpensively these days. I picked up a 2015 iMac with 32 GB of RAM for $200 and run stuff on that system that use up RAM but have modest CPU requirements. That's a lot cheaper than going up a RAM tier with Apple Silicon.

Isn't nearly anything, including buying used car, 'cheaper than going up a RAM tier with Apple'?

Yeah, I do too (prefer no active swapping, but the point was just to clarify not all memory 'in use' is real and will impact anything. Even beyond that, some lower level of actual swapping to an SSD is still worlds ahead of going to older spinner platter HDs.

 

[pshufd]

Isn't nearly anything, including buying used car, 'cheaper than going up a RAM tier with Apple'?

Yeah, I do too (prefer no active swapping, but the point was just to clarify not all memory 'in use' is real and will impact anything. Even beyond that, some lower level of actual swapping to an SSD is still worlds ahead of going to older spinner platter HDs.

You can get pretty good performance with 32 GB of RAM and a 1 TB HDD for a lot of things, particularly cloud applications. Swap at all and it kills your performance. The thing is that RAM on older iMacs is just so cheap: why not? There are programs that use up RAM but not a lot of CPU and they're begging to be run on old and cheap equipment.

And even if swap is okay, why would you want it? Especially if you make your living at it and the cost of hardware is small compared to the revenue generated?

 

[ArkSingularity]

You can get pretty good performance with 32 GB of RAM and a 1 TB HDD for a lot of things, particularly cloud applications. Swap at all and it kills your performance. The thing is that RAM on older iMacs is just so cheap: why not? There are programs that use up RAM but not a lot of CPU and they're begging to be run on old and cheap equipment.

And even if swap is okay, why would you want it?

Some swap usage, in and of itself, doesn't necessarily kill your performance. It depends on how many page faults are actually being triggered and how often the OS is having to grab things from swap. There is usually a fair amount of stuff in memory that isn't particularly actively being used, and much of it can often be thrown into swap for hours with very little impact on performance.

When swap becomes a problem is when page ins start to sharply increase. There comes a point at which you begin to be forced to swap more actively used data, and at this point, it really doesn't matter how fast the SSD is. The system will grind to a halt if it's constantly waiting on swap because the latency is orders of magnitude worse than RAM.

Linux actually keeps track of this with PSI measurements that can keep track of how often processes are waiting on page ins from swap, etc. Mac OS apparently does something similar under the hood with its memory pressure metrics, but information is much more closed off about how exactly this works internally (apparently, the WARN level is based on this, which is what is used to generate the green/yellow/red colors in activity monitor's memory pressure graphs, but I can't confirm.) Even without knowing the specifics of how exactly memory pressure is calculated, you can easily keep track of real-time page ins on Mac OS (iStats menus is one of the easiest ways to do it). Often there can even be several gigabytes of swap usage with fairly minimal page ins, and these kinds of workloads won't typically see a particularly huge impact on performance until the page-ins start to increase.

 

[pshufd]

Some swap usage, in and of itself, doesn't necessarily kill your performance. It depends on how many page faults are actually being triggered and how often the OS is having to grab things from swap. There is usually a fair amount of stuff in memory that isn't particularly actively being used, and much of it can often be thrown into swap for hours with very little impact on performance.

When swap becomes a problem is when page ins start to sharply increase. There comes a point at which you begin to be forced to swap more actively used data, and at this point, it really doesn't matter how fast the SSD is. The system will grind to a halt if it's constantly waiting on swap because the latency is orders of magnitude worse than RAM.

Linux actually keeps track of this with PSI measurements that can keep track of how often processes are waiting on page ins from swap, etc. Mac OS apparently does something similar under the hood with its memory pressure metrics, but information is much more closed off about how exactly this works internally (apparently, the WARN level is based on this, which is what is used to generate the green/yellow/red colors in activity monitor's memory pressure graphs, but I can't confirm.) Even without knowing the specifics of how exactly memory pressure is calculated, you can easily keep track of page ins on Mac OS (iStats menus is one of the easiest ways to do it). Often there can even be several gigabytes of swap usage with fairly minimal page ins, and these kinds of workloads won't have a particularly huge impact on performance until the page ins start to increase.

I used to program program overlays. That is where you manually instruct the linker to bring in a code segment from disk, run the code, then manually bring in another code segment from disk. We had a lot of different tools for managing 8 KB of core to run financial programs in. These days, RAM is plentiful and cheap. You can get Exadata servers with unreal amounts of RAM (and CPU cores and storage).

A lot of my early engineering career was dealing with systems with very small amounts of memory; tiny by today's standards. I don't have to worry about it today as I have a lot of flexibility in avoiding swap at all. If you make your living off your hardware and the cost of additional RAM is small, why wouldn't you just get more of it? Or if you can get a system with a lot of RAM on the cheap, why not?

I see a fair number of people doing this on Reddit. For some reason, there have been a lot of people acquiring 2015 iMacs and asking questions on improving performance. I suspect that it's due to Monterey going off support this fall and people with 2015s dumping them for Apple Silicon. The thing is 32 GB of RAM is $90, so why not? Next year it will be the same thing with the 2017 models and you can throw 64 GB in them. And then the 2019 models the year after that and you'll be able to throw 128 GB.

 

[wegster]

You can get pretty good performance with 32 GB of RAM and a 1 TB HDD for a lot of things, particularly cloud applications. Swap at all and it kills your performance. The thing is that RAM on older iMacs is just so cheap: why not? There are programs that use up RAM but not a lot of CPU and they're begging to be run on old and cheap equipment.

And even if swap is okay, why would you want it? Especially if you make your living at it and the cost of hardware is small compared to the revenue generated?

You're the one talking about older Macs - my post was explaining for people 'worried they need more' that in many cases, they don't.

Where you can add RAM, obviously add it if you need it, especially at today's (not-from-Apple) prices. On AS Macs, plan accordingly but don't fall for the 'all memory in use' when majority if just caching and lazy unloading, etc. If someone is on a newer Mac not allowing user upgrades, then again - lower levels of swapping aren't an immediate issue for most.

Most people asking about 'do they need more memory' are not in a situation where minutes of an hour changes their billing or income significantly. Those that do, well, probably don't need Apple memory usage explained. .

Personally, while I had upgradeable Macs, I upgraded them all to chipset limits for RAM (back when Apple would claim e.g. 4GB max but chipset and OS would handle 8GB, etc.), from HDD -> SSD, but still eventually hit limits. Had no choice to move off of my 2015 MBP 1TB 16GB, as was running out of actively-used memory and slamming up again.st 95% SSD full - if I had more SSD free space, I would have perhaps tolerated it another 6 months or so, but it would have just delayed the inevitable upgrade to 32GB at the time via new system.

 

[Oculus Mentis]

Designing the chip in a way that allows a terabyte of RAM might mean that users who only need 8GB pay a speed penalty. Apple could not accept that

So instead Apple ”accepted“ not to support at all users who need 1TB of ram whilst charging uses who get 8GB as much as if they purchased 1TB Of ram
At least Apple provides units of different colours to better match the mood of its gaslighted, ram deprived, users…

if only Apple would join the plebs of the CXL standard then, perhaps, all those pcie slots in the Mac Pro could be put to good use…

 

[Isamilis]

If the budget is not an issue, I would get as much RAM straightaway. In reality, 8Gb ram is sufficient for lot of light and medium tasks.