Dr. Mac’s Rants & Raves
I’m frequently asked for advice on adding storage to a Mac, so I distilled my thoughts into a checklist to help you decide on your next storage upgrade.
√ How much storage do you need?
If you’re going to use the drive for backups using Time Machine or other software, it’s best to get a disk at least 3X the size of your boot drive.
So, if your Mac has a 512GB solid-state drive (SSD), you want at least a 1.5TB drive, though 2TB would be better (and probably more cost-effective).
√ How will you use the disk?
If you intend to boot your Mac from this disk, you will be happier with an SSD. macOS is optimized to run on an SSD. Booting from a hard drive takes much longer than from an SSD, and almost everything — launching apps, opening applications, opening windows with more than a few files—will feel sluggish.
On the other hand, if you plan to use it for backups or additional storage for your music, photos, or videos, a hard drive will give you more storage for less money. Which brings us to…
√ What is your budget?
Solid-state drives are much faster, but also more expensive than hard drives. For example, a 1TB external USB 3 SSD will cost you around $160, while a 1TB USB 3 external hard drive is approximately $50.
The higher the capacity, the greater price difference.
So, opt for solid-state if you can afford it—it’s way, way faster. But, unless you intend to boot from the drive (or have another reason for needing SSD speeds), a hard drive delivers more bang for your buck.
√ Internal or external?
This one’s easy—unless you’re replacing an internal drive because it died or is too small—an external drive doesn’t cost much a lot more than an internal one, and you (or a service technician) avoid poking around your Mac’s guts.
√ What ports are available on your Mac?
You want to use a port with USB 3.0 or higher in most cases. If your Mac has an available Thunderbolt port, Thunderbolt drives are rarer but can be significantly faster than a USB 3.0 drive. But… Thunderbolt drives are considerably more expensive than USB 3 drives.. So, unless you truly need super-fast storage, USB 3 is going to be your best bet.
√ What brand do you recommend?
None. I buy the least expensive drive that meets my needs. Since all drives fail eventually, I just assume my drives will fail tomorrow and maintain redundant backups of every file on every disk.
√ One More Thing: You might want to consider something like this Voyager Dock if you expect to have more than two external disks:
The Voyager Dock lets me buy less expensive “bare” (aka “internal”) 2.5 or 3.5-inch hard disks, which have no enclosure or power supply so they take up less space while cost less per gigabyte.than separate external drives..
I have more than half a dozen backup disks, so I have a dock with two bays that allows me to mount two disks at a time (instead of just one):
Yes, I still have to swap disks by hand, but that’s a small price to pay for saving me a lot of desk space, needs only one USB port, and cost a lot less than 6 separate external USB drives with enclosures and power supplies.
Trust me: If you need (or think you’ll someday need) two or more additional external disks, you can’t go wrong with either a Single Bay Dock ($34.75) or Dual Bay Dock ($89.75) from Other World Computing.