Do external SSDs have more heating issues than internal? Why?

[drrich2]

I'll open with my situational context, but the TDLR version is I'd like to know why I keep reading about some external SSDs running hot to really hot (like uncomfortable to hold hot) when I never hear anyone talking about how hot Apple's internal SSDs are in anything, including MacBook Airs, iPhones and iPads that don't have internal cooling fans. I found an article on why SSDs get hot at Tech Target.

In early planning stages for hoped for next Mac. I like simple setups best, so I don't have MacOS on one (startup) disc, the Photo library on another disc, etc... Life's simpler (and to back it up with Carbon Copy Cloner) when there's one SSD, and one backup disc (my old Western Digital external HDD). I've got a large Photo library (I'm a standard general home computer user, and our photos are snapshots). Right now, after considerable file pruning, I'm down to 1.1 terabytes on disc, but I like to keep computers a long time. A 4-terabyte SSD would give me lots of breathing room.

Problem: Apple's notorious SSD upgrade pricing - I'd be looking at around $1,200 (plus tax if any). Ouch! Since I've read 256 gig internal SSDs are slower than 512+, I'd bump to 512 even if I chose the external route.

Potential Solution: Get a Thunderbolt (for high speed) external SSD, format APFS, install current MacOS version, use Migration Assistant to pull everything off the external USB-C SSD I'm using with my 2017 iMac. Make it startup disc. Ignore new Mac's internal storage. Save around $600. If the computer ever dies for other reasons or when I upgrade to a new one, I can take the storage with me. Life is good.

Concerns:

-----1.) External storage is slower than internal. If the M4 Macs have Thunderbolt 5, OWC's upcoming $600 4-terabyte external SSD could level most of that playing field, and from what I gather from others, even a Thunderbolt 3 external SSD doesn't 'feel' noticeably different in most general use.

-----2.) External SSDs involve having to haul the thing around with it. If I get a Mac Mini or Mac Studio, not a big deal, but if I opt for a 14" MacBook Pro, kinda awkward.

-----3.) External SSDs are often reported to get quite warm or outright hot, which can lead to thermal throttling or reduced longevity. What if the thing fails years earlier because it runs hot?

So why is an external SSD on somebody's desk with a body designed to serve as a heat sink apt to run so hot, yet I never hear anyone complain about the one in their MacBook Air doing the same thing?

And how concerned should users be about the heat issue?

Disclaimer: I'm not likely to buy a 'ready to plug and play' option like the OWC rather than a housing from A, an SSD from B, DIY an extra (maybe 3rd party) heat pad on top the SSD based on how somebody explained to do in on a forum post, etc...

 

[chabig]

And how concerned should users be about the heat issue?

That was a long post, but I think the answer is that you should not be concerned. I have several external SSDs and they get warm when they are being heavily used, but I wouldn't say hot. When they're mostly idle, they are cool.

 

[PaulD-UK]

"-----1.) If the M4 Macs have Thunderbolt 5..."

We've already seen the die layout of the M4 in the iPad Pro.
It does NOT have TB5. It shows Thunderbolt 4 x4.
I guess it is highly unlikely that M4 Pro/Max dies will include TB5.

However in the Apple Silicon (Arm) Macs forum thread about code numbers for new Macs found in Sequoia betas, there were two next-generation 17,1 17,2 Macs listed in the code.
So maybe some M5 Macs are due to be announced later in Sequoia's year?
If these are 'higher end' models, then we might see TB5 next year, on Max and Ultra Studios?

"-----3.) External SSDs are often reported to get quite warm or outright hot...
I never hear anyone complain about the one in their MacBook Air doing the same thing?"

What is most like to cause excess heat in external NVMe SSD enclosures is the new USB4 ASMedia chip.
Reportedly this chip doesn't run so hot using Windows.
So that's down to Apple and ASMedia presumably not having a product development relationship.
Apple's 'development relationship' is with Intel, the certification authority for Thunderbolt.

But Intel's TB3 chips (in external SSDs) also always ran quite hot as well.
Earlier Intel Macs were always running hot, especially when there was high activity/high data-transfer going on...

So Macs 'running cool' is a post-Apple Silicon thing, and a significant difference is that Apple has designed its own TB3/USB4 controllers for Apple Silicon Macs. They are is no longer using Intel's controller designs and chipsets in their Macs, as they did in the Intel era.

Apple prioritises efficiency and cool-running.
So internal storage in Macs is probably always going to run cooler than external devices made using standard chipsets, and with less regard to heat problems?

SO ever though TB5 products are now beginning to ship, they will be using Intel's reference design chips.
AND Apple doesn't do that.
THEY will design their own.
AND they haven't done that yet - its not in the M4 in the iMac Pro.

And. I guess. They aren't going to be ready any time soon.

 

[BrianBaughn]

What folders are taking up the most room on your current startup drive?

 

[meson]

This topic is something that I've wondered about as well. That said, I'll echo the insight that it likely has a lot to do with the controller chips in the enclosure. With my mini, I use a 1TB WD Blue SN580 with this SSK Enclosure. My wife recently had an external ssd become unreadable (should be recoverable), so I picked her up the same SSD and this SSK Enclosure. While she was waiting on things to come in, I moved a bunch of her working files to my drive. After her parts came in, I transferred several hundred GB of data from my drive to her new drive. My enclosure was laying on my leg during the transfer and got hot enough that it could have left a blister on my leg had I not moved it. Hers did not get nearly as warm. Both SSDs have thermal pads bridging the gap between the drives and the aluminum enclosures.

 

[Fishrrman]

OP:
"I've got a large Photo library (I'm a standard general home computer user, and our photos are snapshots)."

How large is this photo library (by itself)?
Why not just move THAT to an external drive?
Perhaps with other "large libraries" such as movies and music...

I'm going to be presumptuous, but you will NOT like booting/running a laptop Mac from an external drive as a day-to-day experience.

For a "desktop" Mac, things are different (I booted and ran my 2012 Mini from an external SSD for SIX YEARS before I retired it. It still runs when needed "on the back table"). External booting was "the norm" for me for years.

"NVME" type blade drives seem to run "hot" as a matter of course (although my experience with them is limited). It is... what it is. However, I bought a Crucial X9 (USB3.1 gen2) SSD some months back, and am impressed by how cool it runs over time (it's my "experimental" Sequoia OS install for my 2018 Mini).

Again...
With a new Mac -- CERTAINLY with a laptop Mac -- you will become dissatisfied with "external booting" all the time. Before Apple Silicon, Macs ran quite well when booted externally, but this is no longer the case with the new ones. External booting can be done, but it becomes "a chore" that one must put up with. Even on desktops.

I suggest you post "an inventory" of what your large files ARE.
So that we can see what needs to be on the internal drive, and what doesn't.

Finally, have you thought of giving things "a good cleaning out" ???

 

[drrich2]

What folders are taking up the most room on your current startup drive?

How large is this photo library (by itself)?
Why not just move THAT to an external drive?

The Photos library; it's over 600 gigabytes (I've been racking up digital snap shots for decades). In theory, it could be offloaded onto an external drive. On the other hand, I aim for around 8-years out of a computer. If I opt for the internal SSD approach, I need to think about having plenty of room going forward.

Finally, have you thought of giving things "a good cleaning out" ???

I did; I think I ditched about 200 gigs in old files, software that can no longer run, etc... Granted, a lot of those old photos aren't anything special or likely to be used, but they do hold memories. Maybe when I'm really old (mid.-50's now) I'll ditch a whole bunch so our kid doesn't inherit an ungainly mess. I don't work with video much at all; I 'think in stills,' so when designing annual family books, it's all stills, no embedded video, etc...

For a "desktop" Mac, things are different (I booted and ran my 2012 Mini from an external SSD for SIX YEARS before I retired it. It still runs when needed "on the back table"). External booting was "the norm" for me for years.

Again...
With a new Mac -- CERTAINLY with a laptop Mac -- you will become dissatisfied with "external booting" all the time. Before Apple Silicon, Macs ran quite well when booted externally, but this is no longer the case with the new ones. External booting can be done, but it becomes "a chore" that one must put up with. Even on desktops.

For me a notebook would work in 'clamshell mode' the overwhelming majority of the time, excepting rare vacation trips, etc...

I'm curious about the aggravation you find routine long-term external SSD boot drive use on Apple silicone Macs to be. When you say it worked quite well on Intel Macs but not on ASD, what is different that makes it a chore?

I ask not only for myself, but this seems to be an approach fairly often recommended on MacRumors (the external SSD boot disc).

P.S.: My 2017 Intel iMac's Fusion Drive messed up, and I'm using a Samsung T7 Shield USB-C external SSD as my boot drive now (and it's snappier). The only problem is pretty often it restarts due to kernel panics; no idea whether the T7 use is an issue vs. software conflicts, migrating programs instead of fully clean install, etc...

 

[Analog Kid]

So why is an external SSD on somebody's desk with a body designed to serve as a heat sink apt to run so hot, yet I never hear anyone complain about the one in their MacBook Air doing the same thing?

Don't take too much from the source you linked, it's not great. You can find thermal images of SSDs-- the heat from the SSD mostly comes from the controller chip, and it's a function of the data rate you're running the drive at. The flash chips themselves don't get as hot. If you're using an external SSD, you have two controllers running at very high speed-- the SSD controller and the Thunderbolt or USB controller, so more heat. I'm pretty sure the SSD controller is embedded in the M series SoC, so it benefits directly from the sophisticated cooling system in the Mac. The external drive is typically designed to be small, the laptop has a keyboard and display, so more surface area to spread (dilute) and dissipate (eliminate) that heat.

The heat sink on the external drives (or M.2 modules) has a disadvantage of taking the heat from the controller and spreading it to the flash chips.

One benefit of the internal architecture is that the heat of the controller is physically isolated from the storage chips, and it's the storage chips that suffer degradation from heat. The Macs with active cooling often put the flash chips near the cold air intakes, and the controller heat in the SoC feeds directly to the heat pipes that dumps to the hot air exhaust.

Whether you need to worry about this heat is a personal thing. Some people get really focused on these issues. I personally tend to replace external drives for technology upgrade reasons long before they reach their end of their service life.

 

[BrianBaughn]

You have a significant amount of stuff other than the Photos.

My main computer is a 1TB Mac Studio and I have a good bit of external storage connected. I recently splurged and replaced my 2008 MacBook with an M3 MacBook Air. I don't use the MBA like a main unit so not having direct access to the Studio's externals doesn't bug me. If I need a file from there I can use file sharing at home or via my VPN when not.

If I were going with a laptop-only scenario I'd want to boot from the internal and I'd be doing the research on how to make that work with externals to which I don't need access when away from my desk. The solution, if there is one, depends a lot on what one wants to be able to do when un-tethered.

 

[drrich2]

You have a significant amount of stuff other than the Photos.

Yeah. I just went digging and did another outdated old file purge. My current usage:

Total: 1.08 Terabytes.

Photos: 616.62 Gigabytes.
Documents: 254 Gigabytes.
Applications: 94.66 Gigabytes.
System Data: 57.97 Gigabytes.
TV: 16.74 Gigabytes.
Mac OS: 11.65 Gigabytes.
Mail: 5.89 Gigabytes (I've got an old archive going way back)

There's more, but those sum it up. Realistically, my practical options are either get a BTO Mac with at least a 2-Terabyte SSD (and offload that Photos library to an external device) or get a 4-Terabyte SSD (and keep everything on it), or get a 4-Terabyte SSD for an external boot drive, which Fishrrman suspects I'll find irritating to deal with chronically in an Apple Silicon Mac (I'm not sure why).

Unfortunately, the sales I see pretty much all top out at 1-terabyte internal SSD capacities. This matters because if Best Buy has a big sale on MacBook Pros but only goes up to 1-terabyte SSD, and I want 2, if I need to buy from Apple, B&H Photo & Video or wherever and they're not having a big sale, the price differential could be big.

One thing has not changed about the Mac ecosystem over the years I've followed it...the sheer pain of compromise shopping/decision-making.

P.S.: In recent times I've purged over 200 Gigabytes.

 

[PaulD-UK]

As to booting from an external SSD, this post gives an insight into why it has become more difficult with AS Macs.

 

[Fishrrman]

What's in the "documents" folder that is eating up that space?
Are the files in there "active" files (things you touch frequently), or are they just "archived" there (stored and seldom looked-at)?

That photos library belongs on an EXTERNAL "archive" drive.
Actually only one archive IS NOT ENOUGH.
You need at least one backup of it.
TWO backups are better.

For archiving on external drives that ARE NOT used for either time machine or cloned backups, I recommend using HFS+ instead of APFS -- even on SSDs. HFS+ is an older system, but it's "maintainable" by 3rd party drive utilities. APFS is not.

You need to learn how to manage your drive space better.
I sense this is a problem for many folks, who probably don't often access 75% (or more) of "the stuff" that is on their drives...

 

[drrich2]

What's in the "documents" folder that is eating up that space?
Are the files in there "active" files (things you touch frequently), or are they just "archived" there (stored and seldom looked-at)?

Trying to figure out the space thing now. Deleted a bit more. The T7 Shield is my boot disc, and what I use, so I right click it and choose 'manage storage.' It shows Documents as 253.83 GB. Wow, that's big. I'm the only user on this Mac; I open the T7, go to users, my user name folder, and in it Documents - which shows 36.07 GB. Way, way less. I've previously deleted the big bulk of what was in my old Downloads folder, so it's not that (only 3.8 MB). Movies has 180.87 GB; if 'manage storage' classifies the movies as documents, that could explain a lot.

I've been accumulating documents for over 2 decades. Lots of little stuff here and there. Deleted a lot of old stuff recently (including some things I needed to delete).

 

[Fishrrman]

I don't use the "manage storage" at all. Never have.
I don't want the computer "managing" stuff so that I don't have control over "what" goes "where".
But that's just me.

180+gb of movies?
How often do you watch them?
This is stuff that could be on an external drive.
I have a 1tb SSD dedicated to movies and old tv shows. I try to keep as few movies/shows on the internal drive as possible -- next-to-none, almost, stuff I haven't watched yet.
Once watched, an item either goes to the archival drive, or to the trash.

 

[drrich2]

I don't use the "manage storage" at all. Never have.

I just use it to see a breakdown of what's using storage, not to change things.

180+gb of movies?
How often do you watch them?

Did a little digging; looks like old iMovie clip content. Paired it down to 157.56 GB. Yes, another candidate for offloading to an external disc if I get a new system.