External Hard Drives: What to Look at Before Buying One
Including the nuance that the advertised speed also depends on your machine's port.
Before looking at a specific brand or model, these criteria help you sensibly compare any external drive — without relying on a "top 10" list that can go stale within months.
1. HDD or SSD: depending on what you'll store
| External HDD | External SSD | |
|---|---|---|
| Price per TB | Much lower | Notably higher |
| Speed | 100-150 MB/s | 500-2000+ MB/s |
| Shock resistance | Sensitive, even when off | No moving parts |
| Ideal for | "Cold" archiving, backups you rarely check | Active use, editing, portability |
2. The nuance product boxes don't make clear
"Up to 2,000 MB/s" rarely means a constant 2,000 MB/s — that figure is the disk's theoretical maximum, but the real speed you get also depends on YOUR machine's port. If your PC only has USB 3.2 Gen 1 (5 Gbps), you won't exceed around 500-600 MB/s real, whatever figure is on the disk's box. Check what port your machine has before paying for speed you won't be able to use.
3. Capacity based on your actual use
If you're unsure how much you need, our guide on how much storage you need applies equally well to an external disk as to an internal one.
4. Encryption, if you store something sensitive
Some models include hardware encryption with a password — a real layer of protection if the disk gets lost or physically stolen, not just a marketing extra.
Practical warning: always safely eject the disk before disconnecting it. The exFAT format (common on disks compatible with both Windows and Mac) has no journaling — disconnecting without ejecting first can corrupt data that hadn't finished writing yet.
Tip: for genuinely secure backups, combine an external disk with an additional cloud copy — the "3-2-1" rule (3 copies, 2 different media, 1 offsite) is the reasonable standard if your data genuinely matters to you.
Frequently asked questions
Why doesn't my external drive reach the speed advertised on the box?
That figure is the disk's theoretical maximum — the real speed also depends on your machine's port. With a more limited USB port, you won't reach the maximum advertised speed, whatever disk it is.
Is it dangerous to disconnect an external disk without ejecting it first?
Yes, especially in exFAT format, which has no journaling — it can corrupt data the system hadn't yet finished physically writing to the disk.
Is it worth paying more for an external SSD if I only do occasional backups?
For infrequent backups of files you don't need to access quickly, an HDD is usually more economically reasonable — the SSD pays off when you work actively from the disk or need frequent fast transfers.