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External hard drive or SSD for MacBook: which to choose?
An external drive does two things: it backs up the Mac and frees up space. A hard drive costs less per terabyte, while an SSD is much faster and more robust. Here is how to choose, connect and format your drive.
In short: hard drive or SSD?
- Time Machine backup, archives, films: a hard drive is enough. It offers plenty of space for a small price.
- Working on your files (photo library, video editing, projects): an SSD. It is several times faster and is not afraid of knocks.
- A full 256 GB MacBook Air: a small external USB-C SSD to move the big folders.
- You have an old drive or SSD to hand: an external enclosure turns it into a USB drive.
Speeds in practice
| Drive type | Typical speed | Good for |
|---|---|---|
| 2.5-inch hard drive | 100 to 150 MB/s | Backup, archives |
| 3.5-inch hard drive (mains-powered) | 150 to 250 MB/s | Large desktop capacity |
| SATA SSD in a USB enclosure | 400 to 500 MB/s | Everyday use, photo library |
| NVMe SSD in a 10 Gb/s USB-C enclosure | Up to about 1,000 MB/s | Video editing, large files |
| NVMe SSD in a Thunderbolt enclosure | 2,000 MB/s and more | Professional work |
These speeds also depend on the Mac's port and the cable: a USB 2 cable or a low-end adapter limits any SSD to about 40 MB/s.
The port: USB-C or USB-A?
MacBook Air models since 2018 and MacBook Pro models since 2016 only have USB-C (Thunderbolt) ports. Choose a drive or enclosure supplied with a USB-C cable, or add a USB-C to USB-A adapter. Older MacBooks have USB-A ports: a USB-A cable is enough.
2.5-inch drives and SSDs are powered by the cable. A 3.5-inch drive, which is bigger, needs its own mains power supply.
Formatting the drive for the Mac
Open Disk Utility, select the external drive, then click “Erase” and choose the format. Careful: erasing deletes everything on it.
| Format | When to choose it |
|---|---|
| APFS | SSD used only with recent Macs (macOS 10.13 High Sierra or later). Time Machine uses it since macOS 11 Big Sur. |
| Mac OS Extended (Journaled) | Hard drive, or a drive to plug into an older Mac. |
| exFAT | Drive shared between a Mac and a Windows PC. |
Reusing your Mac's old drive
- 2.5-inch hard drive or SSD (MacBook Pro up to 2012, iMac, laptop PCs): it fits in a 2.5-inch SATA enclosure.
- M.2 NVMe or NGFF SSD (the PC format, and SSDs fitted with an adapter in 2013-2017 Macs): it fits in an M.2 enclosure.
- Original Apple SSD (MacBook Air 2010-2017, MacBook Pro Retina 2012-2017): its connector is specific to Apple. It does not fit in a standard M.2 enclosure.
- MacBook since 2018: the storage is soldered to the logic board and cannot be removed.
An external drive is not a backup if it holds the only copy of your files. Keep two copies of what matters.
Our enclosures for an external drive
- M.2 NVMe SSD external enclosure: USB-C to USB-C cable and USB-A adapter included.
- M.2 NVMe + NGFF SSD external enclosure: takes both types of M.2 SSD, USB-C cable and USB-A adapter included.
- USB-C external enclosure for 2.5-inch drive: for a 2.5-inch SATA hard drive or SSD.
- USB external enclosure for 2.5-inch drive: Micro USB-B to USB-A 3.0 cable included.
- External enclosure for 3.5-inch drive: power supply and USB 3.0 cable included.
The enclosures are sold without a drive. Each one is tested in our workshop before it ships.
- Full SSD: upgrading to a larger drive on a Mac
- SSD not recognised by your Mac? APFS vs HFS+ explained
- NVMe SSD in a 2013-2015 MacBook: the firmware that blocks everything
- Data recovery on a Mac: what you need to know
Frequently asked questions
Can you start a Mac from an external SSD?
Yes. You can install macOS on an external SSD and start up from it. On an Apple silicon Mac, hold the power button at startup to choose the drive.
My external drive does not appear on the Desktop. What should I do?
Open Disk Utility: if it appears there in grey, click “Mount”. If it does not appear at all, try another cable and another port.
Does a drive formatted on a PC work on a Mac?
In exFAT, yes, for both reading and writing. In NTFS, the Mac can read it but cannot write to it without extra software.
What capacity should I get for Time Machine?
At least double the space used on your Mac, so that several versions of your files can be kept.
