Questions Regarding How Much Memory Is Needed?

Heat_Fan89

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I ordered my i5 Mini from Amazon and it came with 8GB of RAM. Here are my questions:

1) Do I need more than 8GB if I don't do much multitasking?

2) Do I need more than 8GB if Activity Mon says I'm currently at around 4.6GB as I type this message?

3) If I increase the RAM amount will that decrease or almost eliminate disk writes to the SSD via Activity Mon (currently 867MB)?

4) The i5 Mini is pretty responsive, will the system get even faster with more RAM?
 

velocityg4

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Dec 19, 2004
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Do your normal work with Activity Monitor open to the Memory tab. If memory pressure is in the yellow or red. You need more RAM.
 

Heat_Fan89

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I went ahead and ordered from Amazon a 32GB Kit (Corsair Vengeance) for under $140. I figure it'll be the last time i'll need to upgrade the RAM in the Mini.
 
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Heat_Fan89

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I received my RAM from Amazon today and did the upgrade. It took about 30 minutes because I did not want to break anything. I followed the iFixit video, took my time and everything is working. The toughest part was getting the "tiny' LED connector to seat properly on the motherboard. The FAN connector was tricky cause I kept trying to seat the connector flat onto the motherboard and it just would not go in. I finally found the trick to it and you have to insert the cable on a downward angle then push down to get it to lock.

The system feels no faster than before with the stock 8GB and I'm now using slightly more RAM than I did before.
 
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Ledgem

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Jan 18, 2008
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I ordered my i5 Mini from Amazon and it came with 8GB of RAM. Here are my questions:

1) Do I need more than 8GB if I don't do much multitasking?

2) Do I need more than 8GB if Activity Mon says I'm currently at around 4.6GB as I type this message?

3) If I increase the RAM amount will that decrease or almost eliminate disk writes to the SSD via Activity Mon (currently 867MB)?

4) The i5 Mini is pretty responsive, will the system get even faster with more RAM?
I know you already did your upgrade, but nobody seems to have offered any technical advice. I thought a few bits might be of interest to you.

Regarding your questions:
1) Memory and multitasking - it really depends more on what types of things you're doing with your computer, compared with how much multitasking you're doing. I also use 32 GB in my computer and a single photo-editing application can take up 10-30% of my memory on its own.

2) The amount of memory in use isn't really a useful metric anymore. That's because starting around 3-5 years ago (I can't recall exactly when Apple implemented it) the system began to aggressively use RAM to cache files. This is a good thing because it speeds up your overall system. We used to think that high RAM utilization was a bad sign and meant that you needed an upgrade, but with modern macOS, unused RAM is wasted RAM. Case in point, with my 32 GB setup and only minimal multitasking (Safari, Mail, iTunes, and the host of background monitoring apps I run that don't take much memory), the system is currently using close to 14 GB on cached files. This doesn't mean I need an upgrade! If an application demands memory then macOS will write the cached files back to the disk or purge them. The more memory you have, the more unused memory you'll have, and macOS will put it to work for you by caching more onto it.

Using the Activity Monitor, @velocityg4 offered the good advice of looking at your "memory pressure." If you prefer numbers to graphs, you can look at "memory used," which describes how much RAM is being used by your programs. Basically, if your "memory pressure" is in the green, you should be fine on the RAM front. If you hit yellow from time to time you'll likely still be fine, too. If you're hitting the red regularly then you definitely need more RAM. Of note, I have had some slowdowns even when "memory pressure" just showed an elevated green graph, but I'm not 100% convinced that the problem was purely in RAM. What I can say with certainty is that if your "memory pressure" is a very small, green graph, a RAM upgrade is likely to be a waste.

3) Increasing the RAM should theoretically decrease disk writes (page outs) but it won't eliminate them completely, based on what I see from my system. I can't say with certainty why they're not eliminated entirely.

It's also worth noting that writing to the disk isn't the performance bottleneck that it used to be with spinning, magnetic hard drives. Paging out (writing data from RAM to disk to make space for more things in the RAM) was slow and would slow down other disk operations; modern SSDs are so fast that you usually don't feel it when data is shuffled between the SSD and RAM. It's still nicer to have data cached in the RAM, as it's still faster and does prevent some wear on the SSD (although nearly all consumer SSDs will far outlive the computers they're included in). But reducing page outs used to be some miracle performance boost for systems, and SSD-equipped systems won't perceive such huge performance gains because the SSD was already compensating so well.

4) Speed improvement with RAM really depends on what you're doing, and whether you were RAM-constrained to begin with. Based on your observations, it sounds like you weren't RAM-constrained.
 

Heat_Fan89

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Based on your observations, it sounds like you weren't RAM-constrained.
Thanks for the detailed info. You are probably right but RAM is cheap these days and prior to upgrading the RAM I noticed that just doing basic stuff I was pushing close to 6.5 GB of RAM, and at times I would see compressed memory in the Activity Monitor. I also noticed disk writes in the 1 GB range within 30 minutes. And since the SSD is now soldered i'm trying to cut that down and if adding memory helps, then upgrading was the right way to go.

I no longer have memory compression and my disk writes are in the 250 MB range within 30 minutes. But I don't know if adding RAM cut down on some of the disk writes. I'll have to monitor that.
 

Ledgem

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I'd agree that 8 GB is probably on the lower side for modern systems. I have a bad habit of keeping too many tabs open in Safari, and I've seen Safari alone consume over 4 GB of RAM... not that I'd upgrade purely over that, but it goes to show that you can use even basic applications and still use gobs of RAM. I certainly didn't mean it as criticism of your decision to upgrade - there's certainly no harm in having more RAM, and this should ensure that your system performs well even if you decide to do more intensive tasks.

Having more RAM should cut down on the number of page outs that you're having. Still, I'd want to emphasize that for the overwhelming majority of people you don't need to worry about having more read/write activity on the SSD. There was a study examining failures in drives used in data centers, where the drives are under heavy activity. For 250 GB drives, failures tended to be noted around 700-900 terabytes written (that's 700,000-900,000 gigabytes). To put that into perspective, most swap files are in the megabytes range. Even when I dump my camera files onto my SSD, at most we're talking about 12 GB of files in a go once every other week at best; maybe once a month at most. Looking at my usage, even if I were doing 20 GB of writes per day (which I am most certainly not - I'm probably not doing even half that), it would take me about 96 years to reach the write limit of my SSD if I assume the lower limit of write tolerance. And of course, it's worth noting that the study I'm quoting was from 2014, and that it was only for 250 GB drives; larger drives will be able to withstand more, and more modern drives are also likely to be able to withstand more by virtue of advances.

If you're running a server that is heavily utilized then it may be a different story, and of course you could be doing other things that involve heavy disk activity that make my reassurance meaningless. Assuming you're the absolute average of average in computer use, though, you don't need to worry about swap activity on your SSD and wearing it down.

Enjoy the upgrade, all the same! I'm limited to 32 GB on my current system, and admit that it's probably overkill for my needs - the vast majority of the time I could probably get away with 16 GB, and maybe 24 GB would do for really heavy (or lazy) usage. That doesn't mean I'm not going to go for 64 GB when I upgrade to a system that can take it! ;)
 

Heat_Fan89

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For 250 GB drives, failures tended to be noted around 700-900 terabytes written (that's 700,000-900,000 gigabytes).
Thanks for the detailed information and your numbers are encouraging. I have read that for most modern TLC and QLC 250GB SSD's that TBW (Terra Bytes Written) is around 60-75 TB for the life of the drive. Apple doesn't list TBW so I was concerned that hitting 60 TB in 5-6 years could happen especially with OS installations and OS updates.
 

hagjohn

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Aug 27, 2006
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Get the most you can afford. 16GB minimum though, IMO. I'm happy with the 32GB that I have. Also think about how long you plan on having this computer. Newer OS's may have more memory usage, so buying too low isn't a good thing.
 
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Fishrrman

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Feb 20, 2009
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16gb was "enough" for me.
General usage, photo edits, light movie editing.

I don't like all the "tricks and finagling" that Apple implemented with RAM handling beginning with Mavericks.

I do the following:
- DISABLE VM disk swaps (no page ins or page outs, no disk swapping)
- DISABLE compressed memory

Runs great, NO crashes.
 

Ledgem

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Jan 18, 2008
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Thanks for the detailed information and your numbers are encouraging. I have read that for most modern TLC and QLC 250GB SSD's that TBW (Terra Bytes Written) is around 60-75 TB for the life of the drive. Apple doesn't list TBW so I was concerned that hitting 60 TB in 5-6 years could happen especially with OS installations and OS updates.
Those numbers seem low. I did another search to find more numbers and based on what manufacturers suggest (not what's actually tested) the number is still around 200 TB. The article I initially alluded to didn't discuss what manufacturers said, the number of 700-900 TB is what was actually tested. However you're right that the SSDs used in data centers were probably using SLC SSDs. Even so, the disparity shouldn't be as great. But even if you want to assume 60-75 TB for the life of the system, at around 20 GB per day (which again is likely much, much higher than the average system is being exposed to) you're looking at a bit over ten years before the SSD would reach its limit - and I'm still skeptical of those numbers and believe that the number of years is actually much, much greater. Even going with ten years, you'd likely either have changed your system, or you'd have upgraded your internal drive to something like a Thunderbolt 3-connected SSD that would be faster and larger. It's not worth worrying about.

I suppose if you want to reassure yourself further, you could try to find stories of SSD failure. Pretty much every case I've heard of for standard consumers came down to the controller chip failing, and that was back when SSDs were still pretty new. I'm sure you can find some stories, but SSD failure is pretty rare - far, far more rare than HDD failures were. Your average user isn't performing enough write activity to their SSDs to wear them out.

I'd also recommend against Fishrrman's advice to disable the swap file and memory compression. While it's true that memory compression was created as a solution to improve performance back when RAM tended to be more constrained and we were using HDDs instead of SSDs, which made swap files a prominent performance bottleneck, there's really no good reason to disable it. Modern computers are fast enough that you won't notice a performance benefit. I also don't see the point in disabling the swap file; even if we disagree on whether it's ten years or 100, we've already established that your SSD is likely going to outlast the rest of your computer. By disabling these things you're just handicapping your computer and possibly destabilizing it. Apple, Microsoft, IBM, and all of the other big tech companies aren't perfect, but there's a reason why they still have all of these functions in place.
 
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Heat_Fan89

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Those numbers seem low. I did another search to find more numbers and based on what manufacturers suggest (not what's actually tested) the number is still around 200 TB. The article I initially alluded to didn't discuss what manufacturers said, the number of 700-900 TB is what was actually tested. However you're right that the SSDs used in data centers were probably using SLC SSDs. Even so, the disparity shouldn't be as great. But even if you want to assume 60-75 TB for the life of the system, at around 20 GB per day (which again is likely much, much higher than the average system is being exposed to) you're looking at a bit over ten years before the SSD would reach its limit - and I'm still skeptical of those numbers and believe that the number of years is actually much, much greater. Even going with ten years, you'd likely either have changed your system, or you'd have upgraded your internal drive to something like a Thunderbolt 3-connected SSD that would be faster and larger. It's not worth worrying about.

I suppose if you want to reassure yourself further, you could try to find stories of SSD failure. Pretty much every case I've heard of for standard consumers came down to the controller chip failing, and that was back when SSDs were still pretty new. I'm sure you can find some stories, but SSD failure is pretty rare - far, far more rare than HDD failures were. Your average user isn't performing enough write activity to their SSDs to wear them out.

I'd also recommend against Fishrrman's advice to disable the swap file and memory compression. While it's true that memory compression was created as a solution to improve performance back when RAM tended to be more constrained and we were using HDDs instead of SSDs, which made swap files a prominent performance bottleneck, there's really no good reason to disable it. Modern computers are fast enough that you won't notice a performance benefit. I also don't see the point in disabling the swap file; even if we disagree on whether it's ten years or 100, we've already established that your SSD is likely going to outlast the rest of your computer. By disabling these things you're just handicapping your computer and possibly destabilizing it. Apple, Microsoft, IBM, and all of the other big tech companies aren't perfect, but there's a reason why they still have all of these functions in place.
Thanks again for the explanation and reassurance, much appreciated !
 

marclondon

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Aug 14, 2009
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I'd agree that 8 GB is probably on the lower side for modern systems. I have a bad habit of keeping too many tabs open in Safari, and I've seen Safari alone consume over 4 GB of RAM...

Safari was taking 19GB - yes 19GB - on my Mac today. A lot of tabs open over a week or so. That the Mac was still running is a tribute to the i7 and 32GB ram I put in.
 

Heat_Fan89

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Safari was taking 19GB - yes 19GB - on my Mac today. A lot of tabs open over a week or so. That the Mac was still running is a tribute to the i7 and 32GB ram I put in.
I had just one tab open on my 2018 Mini and it was around 6.5GB and it was starting to compress memory. That's when I decided to upgrade the RAM. Weird how MacOS has gotten to the point where you need more and more RAM just for a basic functional system. With Windows 10 Pro i'm usually no more than 1.9 GB min and 4.5GB with multiple programs open.

The flipside I was able to use one of my spare Mini SO-DIMM's and put it in another Windows PC and bumped the RAM from 8GB to 12GB.