Booting M1/M2 Mac mini from an external bootable USB 3.0 SSD

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Booting M1/M2 Mac mini from an external bootable USB 3.0 SSD

There is no way I would pay the ridiculously inflated prices for more RAM or storage so my only choice is the base model.

The main concern I have about the base model Mac mini is the 8GB RAM necessitating a lot of swapping when using apps like Final Cut Pro.

I am not bothered by the small 256GB SSD as I already have 3 USB 3.0 SSDs totalling 2.275GB.

I want to know what happens with swap memory if I boot the mini from one of those SSDs.

Would the swapping occur on the mini's internal SSD or on the large bootable external SSD?

It would be great if it occurred on the large, cheap external SSD but I suspect it may still continue on the overly expensive, irreplaceable internal one.

Can anyone clarify the situation for me?

Mac mini, macOS 10.14

Posted on Apr 30, 2023 10:20 AM

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Answer 1

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wjpjr

Level 1

101 points

Apr 30, 2023 3:39 PM in response to Ian R. Brown

Ian R. Brown wrote:

I want to know what happens with swap memory if I boot the mini from one of those SSDs.

Would the swapping occur on the mini's internal SSD or on the large bootable external SSD?

Can anyone clarify the situation for me?

When booted from the external SSD, macOS will swap to the external SSD. You might want to view this YT video, https://youtu.be/5rj5zRQe3rI. The user in the video seemed to uncover an issue with high memory pressure and swapping to his external SSD when running many apps causing the swap to go into the 10+GB range. Personally, I've not seen this issue when my M1 mini is booted from its external 1TB TB SSD although the apps I use in my workflow don't cause my memory pressure to go into the red. Hope this helps..

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Answer 2

den.thed

Level 10

81,736 points

Apr 30, 2023 11:53 AM in response to Ian R. Brown

It would be best to fork out the extra bank for at least the 16GB option.

Booting from an external USB 3.0 SSD is like 4 times slower than booting and running from the internal storage.

Best bet, is to run the macOS and Final Cut Pro on the Mac mini's internal storage, then store your projects on the larger external SSD(s). see > Move a Final Cut Pro library - Apple Support

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Answer 3

Ian R. Brown Author

Level 7

22,145 points

May 1, 2023 12:58 AM in response to den.thed

From over 20 years experience I can categorically state that the "recommended" required RAM is grossly exaggerated mainly for the profit of the manufacturer and as a result the myth that you can't get enough has been propagated.

I have only ever bought computers for video editing and up to 2014 I too used to add extra RAM and help spread the myth.

When I bought my new 27" iMac with only 8GB RAM in 2017 I intended to automatically add extra RAM as soon as possible but luckily I delayed the action and discovered that the machine actually flies effortlessly with that amount.

I have been using Final Cut Pro X since the day it was available in June 2011 and before that the old legacy Final Cut Pro and Final Cut Express.

My 6 year old iMac with 8GB RAM absolutely zips through editing 4K and 1080p video. I regularly have up to 6 layers (tracks) of 1080p composited green screen video on my timeline which play back natively without any need to render and export in around half the film's runtime.

So I have no doubts that for editing purposes the Mac mini's 8GB RAM is more than I would ever require from a purely user experience point of view.

The machine is, after all 3 times faster than my current iMac judging from bench test results and users practical "real-world" testing.

No, my only concern is about the effect of swap memory on the fixed internal SSD but that again is almost certainly an exaggerated worry as I am unlikely to do enough work to affect it in the next decade . . . but I am once again caught up in the scaremongering propaganda.

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Answer 4

Ian R. Brown Author

Level 7

22,145 points

May 1, 2023 1:19 AM in response to wjpjr

Thanks. That more or less reassures me that the external is most likely to suffer any effects of adverse wear due to swapping.

That guy is obviously working under worse-case scenario conditions that I could never envisage.

I'm not sure why anyone would have dozens of browser tabs open simultaneously together with multiple high demand applications.

I must admit that I frequently have a number of other apps and a few browser tabs open accidentally when I am editing but have never noticed any slowdown and if I did it would be a simple task to close them.

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Answer 5

wjpjr

Level 1

101 points

May 1, 2023 3:37 AM in response to Ian R. Brown

Ian R. Brown wrote:

Thanks. That more or less reassures me that the external is most likely to suffer any effects of adverse wear due to swapping.

I'm not sure why anyone would have dozens of browser tabs open simultaneously together with multiple high demand applications.

Yeah I think you will be okay. Although if the external USB 3 turns out to be a speed bottleneck you can always replace it with a DIY TB NVMe drive. Some prices of fast NVMe PCIe 4.0 drives have fallen well below $100 USD, looking at you Sabrent Rocket PCIe 4.0 1TB and a good TB 4 case, Acasis, can be had on sale sometimes for either under or close to $100 USD. Both sold on Amazon. Those two combinations would net a speed close to the theoretical four PCIe lane TB 3/4 speed of approximately a little under 3GB/s. I'm using Sabrent Rocket SSDs and Acacias TB cases exclusive as external drives on my M1 mini and Studio Ultra Macs.

I guess I could be considered a tab hoarder, LOL, having somewhere between 200 to 300 tabs open while researching a project.

FYI, You do want to pay attention to possible latent memory leak bugs currently in Ventura and will probably never get resolved now that the next version of macOS will be demoed in a little over a month at WWDC. Big Sur and Monterey still have some that have not been fixed. Sometimes these memory leak issues might impact the memory pressure causing undue memory swapping that will either slow the Mac down to a crawl or cause the "You have run out of Application memory" error. Both of which will force you to either close the running wild applications or restart the Mac.

Good luck..

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Answer 6

May 1, 2023 5:00 AM in response to Ian R. Brown

FWIW, if your drives are USB 3.0, swapping will be slow and the general experience will be a bit slow. Practical transfer speeds are around 350-450 MB/s.

If you want to boot and run off external, you will definitely want to go with a Thunderbolt/USB4 SSD. Be aware that DIY TB drives can be a problematic adventure as not all NVMe/Enclosure/Operating system combinations work well so you simply cannot just slap something together and expect high performance. You will need to do due diligence and research to find the right combination for your Mac. Also note that spending for the fastest possible NVMe drive is a waste of money as Thunderbolt/USB4 will ultimately limit transfer speeds to to around 2600-2800 MB/sec with an "ideal combination" of drive and enclosure. So, spending money for NVMe with speeds of 5000-6000 MB/sec is a bit of a waste as those speeds are only achieved on internal computer bus.

I personally am using using a 1TB OWC Envoy Pro SX Thunderbolt 3 drive as a boot drive with an M1 Mac and it is performing quite well. My machine has 8GB RAM and I do lots of RAW photo processing and can attest that yes swap is being used and the swap is done to the external drive. While processing is somewhat faster on the internal, the difference running on the external to me is not that significant plus all the wear and tear is happening on the external which is easily replaced.

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