External SSD for the new Mac Mini M4

just about any manufacturer's drives will work. but please be sure to NOT use any of the manufacturer's software that supposedly makes a drive "machine ready". when you use software from just about any manufacturer for their storage device you run the risk of that same software not being compatible with macOS updates / upgrades. it can cause the software to stop working. at best this will cause you a headache. at worst it can render your data inaccessible. it is always best to use disk utility to erase and format a drive before use to remove any preloaded software.

please see Erase and reformat a storage device in Disk Utility on Mac - Apple Support

as far as the crucial external SSDs, they do have a good reputation with apple compatibility. if it was me, I would also visit OWC’s website and see what they have to offer.

VikingOSX wrote:

If your purchase criterion is speed, then the OWC Envoy Ultra will do 6000 MB/s via the TB5 port on the M4 mini. This is orders of magnitude faster than the Crucial drives capability. OWC has a long history of providing Mac-compatible solutions.

OWC claims that the OWC Envoy Ultra will do "over 6000 MB/s" when connected to a Thunderbolt 5 port – such as the ones on the M4 Pro Mac mini.

The OP said they bought "the basic mac mini model with 250GB space." That one has a plain M4 – and so, it has ports that support Thunderbolt 4 and USB4 40 Gbps. OWC says that the Envoy Ultra will do

• "over 2800 MB/s up to 3800 MB/s" when connected to a Thunderbolt 4 port
• "over 3800 MB/s" when connected to a USB4 port

That's still extremely fast, but here the plain M4's ports aren't fast enough to get the last bit of performance out of that Thunderbolt 5 drive.

If your purchase criterion is speed, then the OWC Envoy Ultra will do 6000 MB/s via the TB5 port on the M4 mini. This is orders of magnitude faster than the Crucial drives capability. OWC has a long history of providing Mac-compatible solutions.

I am using a Crucial X9 (not the Pro) as my Time Machine backup drive on the new M4 Mac Mini Pro. The synchronous speed of the Pro model wasn't necessary for Time Machine.

USB 3.1 Gen 2 runs at up to 10 Gb/s (1250 MB/s). USB 3.2 Gen 2x2 runs up to 20 Gb/s (2500 MB/s), but as far as I know, no Macs support the latter. People who have plugged USB 3.2 Gen 2x2 drives into USB4 / Thunderbolt ports on other Apple Silicon Macs have reported that the connection falls back to USB 3.1 Gen 2 speed.

I would expect the same to happen on your M4 Mac mini.

There is the possibility that Apple quietly upgraded the plain M4 chip to include support for USB 3.2 Gen 2x2 … but I wouldn't count on it. USB4 standards apparently define THREE incompatible "up to 20 Gbps" USB transfer modes. One of the new ones (USB4 20 Gbps) is mandatory for USB4 host ports, but there are few accessories that support it yet. USB 3.2 Gen 2x2 is optional for USB4 host ports, and in effect, was "thrown under the bus."

This said, I'm using a couple of Crucial X9 Pros, and am happy with them. One stores Music and TV libraries - and speed does not appear to be an issue even when playing back 4K Digital Copies of movies that I've redeemed from Movies Anywhere and the iTunes Store. The other I use for incremental backups – no problem there, either.

I Use TB enclosures with WD Black NVME drives with my Mac Mini M4 pro and works great. At present the TB5 drives are scarce and expensive. Your internal 256GB drive speed is about equal to the TB4 external drive speed(the 512GB is faster).

asif_rn wrote:

Regarding manufacturer's software, any idea if "Crucial X9 Pro for Mac" comes pre-formatted or it also needs to be formatted?

It looks like the "Crucial X9 Pro" and "Crucial X9 Pro for Mac" differ in these ways:

• The Mac version comes pre-formatted with APFS, instead of with exFAT.
• The Mac version has a light brown case, instead of a dark grey one.

It does not take long to use Disk Utility to reformat the "PC" version as an APFS drive. So you could buy based on whichever version is on sale for a better price, or has a case color that you prefer.