My system has 49.1 GB In Use, 59 GB committed and 58.4 GB cached files. RAM isn't wasted in modern operating systems.
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ssd swap - high usage of Terabytes Written
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My system has 49.1 GB In Use, 59 GB committed and 58.4 GB cached files. RAM isn't wasted in modern operating systems.
Performance with 11.4 will be the same or higher... System will use more RAM which is faster than SSD. And with full RAM macOS will use SSD swap. Before 11.4 it was that macOS used swap even with no full RAM. So you do not have to worry about performance.
yep, as I said there was indeed an issue/bug before 11.4 where macOS used swap more rather using the available RAM.
If you have enough RAM, you never swap. I generally keep an eye on Activity Monitor to avoid swapping on my systems.
No multiply data units by 512 (even for 256GB Mac) and divide by 1,000,000,000, as @jdb8167 said in post #2765 above.
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I know that generally speaking, a healthy number is about 5GB/hour. Lets say you use your laptop for 10 hours a day, so you end up with around 50GB/day. This number is considered very good.
Question is, would 100GB/day still be considered fine, or is it slowly creeping into the dangerous/unwanted area?
Question is, would 100GB/day still be considered fine, or is it slowly creeping into the dangerous/unwanted area?
Well 100 GB/day is 36.5 TB/year.
A 1 TB SSD is presumably rated for snout 5000 TBW.
so a 512 GB SSD for about 2500 TBW.
A 256 GB SSD for about 1250 TBW.
And a 128 GB SSD for about 625 TBW.
Do the math 625/36.5 = 17 years For the smallest SSD.
There is your guess.
That's not true (at least at 16GB). OS X aggressively caches files and safari windows. For better performance, it assumes (correctly) that frequently used data is best kept in memory at the expense of infrequently used.
The system has swap and it doesn't mind using it.
FWIW, I have a 16GB/1TB MBA and i'm averaging around 1TB/day. 150TB over the last 5-6 months.
smartctl says that's about 6% of lifetime usage.
Thanks dieselm. Now we can add yours.
6% looks a bit high relative to the rule of thumb derived from the above in this post : "Apple M1 SSDs are good for about 5,000 TBW for each 1 TB of capacity."
150TB on a 1TB machine should be more like 3%, if my arithemetic is right
@dieselm what percentage does the Mac Analaytics Data give? see this post if you missed it.
Dieselm 6% 150TB 1TB
6% looks a bit high relative to the rule of thumb derived from the above in this post : "Apple M1 SSDs are good for about 5,000 TBW for each 1 TB of capacity."
150TB on a 1TB machine should be more like 3%, if my arithemetic is right
@dieselm what percentage does the Mac Analaytics Data give? see this post if you missed it.
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I’m curious if your percentage used changed after installing Big Sur 11.4. There is a questionable article that is claiming that SMART reporting has changed. I know that the data units written hasn’t changed but my percentage used is still at 0% so I don’t know about that value. Also, can you do the test from this post and post the data units written, percentage used, and percentage used normalized.
I’m still at 0% used at just about exactly 10 TBW. On a 1 TB SSD. So not terribly useful info.
It is likely that the percentage used goes up faster if the drive is mostly full. More write amplification occurs when the drive has fewer empty blocks available.
That's weird...I have an MBP16 with a 1TB SSD and slightly greater usage, and am still at 2%:
I recently upgraded from Catalina to 11.4 on my Intel Mac, and the Smartctl percentage did not change.
It's 6%. Nothing shows up in Mac Analalytics Data with that filter. Here's the exact data.
Fwiw, my ssd is usually full and someone in the forum said that might make a difference.
Either way, the usage doesn't make much difference to me. At the current rate, it'll be 7-8 years before the SSD burns out and I'll have long since sold it by then.
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The 16" has different type of flash chips that might have higher endurance. Or, you had less write amplification than the other user so the actual NAND writes are lower on your device.
Data Units Written is only half the story.
I run my Macs so that there's no swap. If it gets close, I just close programs and put them on another system.
It's just a lot easier running with no swap at all. That's why I have 128 GB of RAM in my main desktop.
That works out to a TBW drive total of 2500 for 100% or a life span of ~6.9 to 8.3 years assuming linear consumption.
That works out to be a range of 11,993 (assumes actual 1.5...1%) to 7160 (assuming 2.4999999...%) TBW before 100% is reached. I would go with the lower of those or ~7160 TBW
I made two applets in Automator, based on smartctl, to monitor the TBW consumption on my M1 Air. One for quick monitoring from dock, the other starts or stops the service in the background, which periodically displays messages about the current TBW level, and should alert if it gets too high. It also keeps a consumption log, which can be viewed by the first appt, or after stopping the service on the desktop. It monitors every half hour. The logic is not perfect, but it works. For the first run, you have to type xattr -rc in the terminal and drag the applet to the terminal window to get the path to it, and then press Enter. (So that the security system doesn't block the app from an appstore and not from a trusted developer)
So far, I've only encountered one app that caused a huge TBW drain. Parallels for M1 with Windows 10 ARM installed, while installing programs into it, was causing 10 times the amount of programs to be installed. I installed 40Gb of programs and the TBW consumption was 420Gb. The virtual Windows HDD was on an SSD connected to type C, but the increased SSD consumption was for the internal Apple SSD. Of the programs I use, there are no other programs that are causing too much consumption. Perhaps there are others.
My total TBW consumption now on the Air 8/256 for the period March 11 - June 6 is 3.97 TB.
So far, I've only encountered one app that caused a huge TBW drain. Parallels for M1 with Windows 10 ARM installed, while installing programs into it, was causing 10 times the amount of programs to be installed. I installed 40Gb of programs and the TBW consumption was 420Gb. The virtual Windows HDD was on an SSD connected to type C, but the increased SSD consumption was for the internal Apple SSD. Of the programs I use, there are no other programs that are causing too much consumption. Perhaps there are others.
My total TBW consumption now on the Air 8/256 for the period March 11 - June 6 is 3.97 TB.
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Is Microsoft somehow involved in a Mac problem, bug, kernel panic, inefficiency or pain in the butt? How surprising! 🙂
haha... It's actually not.
If Windows runs in a VM, Window's writes go to the virtual disk, which is just a file on your mac. This file runs on APFS, a write-anywhere and copy-on-write file system with snapshots on. This can easily amplify your writes.
Also: Just because a program is just 40GB in size, it doesn't mean it writes 40GB. Windows installers often unpack to temp them copy or move their files to the destination. Windows might also page-out inside the VM if you gave the VM too few GB of RAM.
Main limitations when running VMs are RAM and Disk I/O in almost 90% of cases. CPU is usually not of an issue even though people always think it is.
RAM was cheap up until last fall where prices have more than doubled for high-density sticks. I have not checked prices of NVMe since last year I think but I think that SATA3 SSDs are still fairly cheap. RAM just makes life easier but, as with GPUs, it seems like market prices are catching up with Apple's traditional high prices.