A reason for M1 Macs' excessive writing to NVMe SSD

[trs96]

This youtuber claims he's determined what is really going on with the swap memory writes to M1 Mac SSD drives. Liam at Created Labs has found why new M1 Mac mini and MacBooks write so much data to disk every day. Watch the video and comment if you think he's right or wrong.

 

[pastrychef]

This youtuber claims he's determined what is really going on with the swap memory writes to M1 Mac SSD drives. Liam at Created Labs has found why new M1 Mac mini and MacBooks write so much data to disk every day. Watch the video and comment if you think he's right or wrong.

I think that the "bytes written" includes how much the apps have written and it may have nothing to do with swap memory.

Also, 20+ days vs 3 days is a big difference.

Apple should just make systems with more RAM available and make it available for more reasonable prices. I don't know why they have such tight RAM configurations.

IMO, 8GB is just not enough for a modern system running macOS. I feel that even 16GB is just borderline acceptable. If you've ever used any of the MacBook Airs up to the 2017 model, you will know how lack of RAM really drags down performance.

 

[trs96]

Liam has said he'll continue testing and post a follow up video. I'll be looking at that to see if he gets similar results over the longer term. It appears that Apple will fix this mostly with Big Sur updates over the next few months. It will be interesting to see what happens in 2021 iMacs and the new ASi Mac Pro that will eventually be released. Those will get a lot more ram to meet the needs of professionals.

 

[trs96]

Apple should just make systems with more RAM available and make it available for more reasonable prices. I don't know why they have such tight RAM configurations.

I think they've limited the ram on the entry level M1 models released last November so that they don't end up in the hands of Pros that usually buy more expensive Macs for their work. The 8 core M1 chips beat every Intel CPU in single core performance. If you could buy a mini with 32GB of ram right now to do Pro level work, it would likely keep many from spending a lot more for a new ASi iMac later this year or a MP next year. That is probably also why they dropped eGPU support and will drop AMD graphics support too.

An M1 Macbook Air at $999 or Mac mini at $699 isn't really intended for video editing or other ram intensive tasks that require more than 16GB. Some people are using them for that, especially the M1 mini which stays cool and quiet and doesn't thermal throttle under intensive workloads.

 

[craighazan]

When this story first popped up, I'd already purchased but hadn't received my M1 MBA, and I was genuinely concerned. I don't really use Microsofts suite of Apps or Adobe's, I also don't use Firefox or Chrome and I don't have Rosetta 2 installed on my machine. I was given the option to install it, but I chose not to, my thinking being I can wait for the M1 version of the software.

After watching the above video I checked my 'kernel_task' to see how much it had written since the last time I restarted my machine, about a week ago after updating to 11.2.3. And 'kernel-task' has only written just over a GB since then. So I have to assume it's Rosetta 2 related.

I disagree with pastrychef on weather 8GB is enough to run a modern Mac OS, I think it is, the animations and transitions in finder are insanely smooth. The difference between Big Sur on my Cube with 32GB ram and MBA with 8GB ram is noticeable , the cube can't compete!. The 'Pros' will just have to wait for extra Ram for their requirements, but for non 'pros' like me, it's the sweet spot!.

 

[trs96]

After watching the above video I checked my 'kernel_task' to see how much it wrote since the last time I restarted my machine, about a week ago after updating to 11.2.3. And 'kernel-task' has only written just over a GB since then. So I have to assume it's Rosetta 2 related.

The M1 MBA target market is for people like you that use it more like a conventional, general use "budget laptop." When it performs way better than most Ultra Books that cost a lot more, you know Apple has a winning product. Would be great if you posted your results in the comments section of that YT video.

The primary lesson of this whole story all about optimization. When Apple creates the SoC and then optimizes their apps and programs for it you get a completely different result than running apps via a translation layer such as Rosetta 2. Because of the ram being so close in physical proximity to the CPU/GPU etc. their ram has a much faster level of performance than what you get in a PC with ram installed to the DIMM slots. The M1 MBA's integrated graphics also performs much better than anything Intel offers right now. That's the reason it's a much smoother experience than you get with the cube.

 

[pastrychef]

I think that keeping RAM options low also helps with the planned obsolescence of these system.

 

[UtterDisbelief]

So I have to assume it's Rosetta 2 related.

As I understand it Rosetta 2 interrogates the Intel app and builds some kind of database for it. I've read about this but have no idea how much or how big this DB might be. Seems it does this for each individual Intel app that is run. It's a one time thing though and after the initial run, launches are quicker thereafter.

 

[UtterDisbelief]

I think that keeping RAM options low also helps with the planned obsolescence of these system.

It's curious though, isn't it, that 8GB has been Apple's target RAM quota on its "domestic" machines for a few years now. No idea what they are thinking ...You may be right.

 

[trs96]

It looks like Intel may eventually stop Apple from including Rosetta 2 in "certain regions" due to legal restraints. If so this will solve much of the NVMe SSD wear issues. No Rosetta 2 means no x86 based apps can run in emulation on the new M1 Macs. Intel is no longer "playing nice" with Apple since the big breakup.

Apple may disable Rosetta 2 on M1 Macs in some regions, macOS 11.3 code suggests - 9to5Mac

Just like the original Rosetta technology, Rosetta 2 lets users run macOS apps from one platform on another — this...

9to5mac.com