Many of the NVMe M.2 drives on Amazon and Newegg are labeled “internal”. In fact virtually none are labeled “external”. If you search for “NVMe external” you get only packages of drives and enclosures which are almost always more expensive than buying the parts separately.
So my question is –
what are the key specifications that need to match or be “close enough” for the drive and the enclosure to at least have a reasonable chance they are going to work and deliver the expected performance.
I would use the external drive on a Mac mini M4 Pro – so I have TB4, but USB 3 or 4 with right specs (and without TB designation) would be just fine and is usually a bit less expensive.
Thanks for sharing the amazing collective wisdom of Tidbits.
Internal only means they come without an enclosure. So you need to supply the NVMe enclosure that also provides the bridge from NVMe to USB or TB. It’s a good idea to stick to those, as often pre-packaged units are a ripoff — either because they are offensively expensive or because they package sub-par flash. And you want to get the right flash.
On an M4 Mac right now for the enclosure/bridge you want either 10 Gbps USB3 or 40 Gbps TB4/USB4. The former is great for media libraries or TM (since TM i/o is throttled by macOS). You want the latter to run your system off of or because you have a very high b/w application in mind. USB3 enclosures are inexpensive. USB4/TB4 are roughly 3-4 times as expensive. If your flash is very high end, you don’t want to bottleneck it with a 10 Gbps bridge and so you’ll be inclined to look at USB4/TB4 enclosures. OTOH if you’re building a TM drive and you know your transfers are going to be throttled anyway, getting expensive flash is likely wasted money.
Here are two examples of such enclosures. Both do their thing just fine. Just make sure you match enclosure/bridge performance to flash performance.
NVMe doesn’t have an “external” interface. It is a variation on PCI Express customized for flash storage devices.
Any external SSD will be advertised using a standard external interface (most likely USB or Thunderbolt). While the product description may mention the interface used by the SSD module within the device (probably NVMe, but may be SATA for lower-end devices), that information is pretty much irrelevant for external use, since you will only be connecting the external interface.
So when you go searching for an NVMe device, especially if you’re also searching for “M.2” - the most popular form factor these days for NVMe devices - you are only going to find internal devices.
Wich is not a problem. As @Simon says (sorry), you can mix-and-match almost any NVMe device with any NVMe enclosure and it will work. The only real issues are:
Make sure you really have NVMe. They also make SATA devices in the M.2 form factor, and they will have much lower performance. So make sure both the (internal) SSD and the enclosure are NVMe. Some enclosures may support both NVMe and SATA, but be sure to avoid a SATA-only enclosure.
Make sure the speed of your SSD and the enclosure are appropriate for your application. Don’t pay extra for high performance if you don’t need it, but make sure you do get high performance if you do need it.
Make sure the two parts physically fit together. If the electrical connection physically fits, then they should be electrically compatible (e.g. SATA and NVMe put notches in different places, which should match key-posts in the enclosure’s socket), but they also come in different lengths
A typical SSD will be the “2280” size, meaning 22 mm wide and 80 mm long. But they also make shorter ones (30, 42 and 60mm) and longer ones (110 mm). If you get one of these, make sure your enclosure can accommodate it. If the enclosure is too short, your SSD won’t physically fit. If it is too long, there may or may not be standoffs at the position you need to properly secure the SSD in the enclosure.
Any SSD you shop for should include its size as a part of the description. And any SSD enclosure should include a list of sizes that it can accommodate. For example, the Orico SSD that @Simon referenced supports 2230, 2242, 2260 and 2280 sizes. But the MAIWO enclosure only supports 2280 (according to the Amazon listings).
I will likely go high speed just to future-proof the investment (at least partially).
Simon, In that context, the USB-4 enclosure you linked to is ~1/3 lower cost than most of the alternatives. That is particularly striking since Thunderbolt compliance is a costly feature – which isn’t required for Apple USB-4.
But the reviews include a relatively high percentage of negative comments – heat, loud fan – which is “optional”, i.e., not incorporated in the case – not a desirable approach-- and frequently not performing to specs (although those comment are often hard to tell if the computer being used and even the drive being used. But some sounded pretty well documented.
I will likely go with the OWC Express 1M2 or ORICO 40Gbps M.2 NVMe SSD Enclosure (for which the price has just dropped)-- although the “Tool-Free” feature has been criticized as having greater risk of the drive getting loose and short-circuiting against the enclosure – but I won’t be traveling with mine.
Again, thanks so much to both of you for resolving my question. Greatly appreciated.
If you use a metal enclosure and a thermal pad (which any good case should include) to connect the SSD with the enclosure, then it will be able to dissipate the heat. The case will get warm/hot to the touch when experiencing a lot of activity, but in my experience, it doesn’t get hot enough to cause the SSD to thermal-throttle (which will kill all semblance of performance).
An enclosure with a fan (or placing a passively-cooled enclosure in front of a separate fan) will keep the case cool to the touch, if this bothers you.
On an M4 Pro I see better performance from the same high-end flash with USB4 than with “TB4”. So why should I pay $60+ extra just because somebody certified TB because they think they can then get away with overcharging and underdelivering? Here, USB4 actually does 3.2 GB/s which is the best rate I can get on this Mac using any enclosure money can buy right now. Not 2.8 or 2.1, but the full b/w available over the available PCIe lanes.
(On an Intel Mac things are different. But since this thread is about M4 Macs I’ll stick to commenting on just that.)
The enclosure I linked to is deliberately the version without fan. It performs well for the various flash sticks I have used it with here. I don’t see any heat issues. Or throttling for that matter. Like Howard Oakley, I do not see any benefit from a noisy fan. I tried enclosures with fans and the only real difference I could ever tell is that the fan made noise. No performance difference. I exterminated all my HDDs because I hate noise, the last thing I want is to make silent flash noisy. As long as I get 3.2 GB/s and no throttling, no fan is getting close to my sticks. I have yet to see any excessive heat and thus it also comes as no surprise that I have yet to see any stick fail due to heat. It’s a non-issue, here at least.