NAS vs External Hard Drive for Windows: Speed, Sharing, RAID and Backup Guide

What each option actually is​

A network-attached storage (NAS) device is a small, dedicated computer that holds one or more drives and serves files over your network. One description puts it as a computer in itself, with its own processor, RAM, and a dedicated operating system that manages all data traffic. Because it sits on the network, multiple users can access photos, videos, or backups simultaneously.

An external hard drive is simpler. It plugs directly into a PC, usually over USB, and is generally used by one computer at a time. It's portable, cheap and needs almost no setup.

The real difference is how the storage is connected and managed. Capacity is secondary. Some points often get blurred:

• A NAS isn't automatically bigger. A multi-bay model can grow by adding drives or, on some models, an expansion unit. A single-bay NAS can't.
• Synology's DS923+ is a useful example. Its datasheet describes a four-bay unit that can be extended with a DX517 expansion unit to a maximum of nine drives. It lists two 1GbE ports, with optional 10GbE through an upgrade module. Those are model-specific figures, not a rule for all NAS products.
• Many NAS enclosures ship without drives, so the cost of a NAS includes the disks.
• An external drive's capacity is fixed. You can replace it or add another one, but you can't grow it.

Sharing and access​

A NAS helps when several people or devices need the same files. Nobody has to pass a drive around the office or the house. Its usefulness depends on your network, permissions and configuration. Remote access isn't automatic either. It has to be set up, and it has to be secured.

An external drive wins on simplicity. One reviewer's comparison table lists setup of under 5 minutes (plug and play) for an external drive versus 30 minutes to a few hours for a NAS. That table is one publisher's estimate rather than a measured standard, but the direction is right. A NAS also needs to be powered on and reachable whenever someone wants a file.

Speed: where the original comparison goes wrong​

The TechRadar piece mixes up units. It quotes NAS speeds in "Mbps" when the figures look like megabytes per second, and the two aren't interchangeable. Megabits per second (Mbps) measure line rates. Megabytes per second (MB/s) are what Windows shows in a file copy dialog, and one MB/s is roughly eight Mbps.

It also compares USB interface ceilings with typical NAS results, which isn't like for like. Interface maximums aren't real-world drive speeds.

• The USB Implementers Forum lists three USB 3.2 transfer rates: 5, 10 and 20Gbps. It notes that products work at the lowest common speed of the connection.
• USB 2.0 tops out at 480Mbps, per the USB-IF.
• A spinning hard disk, internal or external, generally can't fill a fast interface by itself. A NAS with a single gigabit link tops out well below a good USB 3 connection, and shared traffic or Wi-Fi can slow it further.
• Two 1GbE ports don't mean a single client gets double the throughput.

In practice, a directly attached drive is often quicker for one big copy to one PC. A NAS wins on convenience when many people need the files. For everyday documents and photos either is fine. For large video projects, check the network path and test your own workload.

Backup and redundancy: the claim to push back on​

TechRadar says data is "safer on a NAS than on a hard drive." That's too strong. A NAS can offer better protection against a single drive failure, but protection against drive failure isn't the same as a backup.

• Failure tolerance is real. An external drive has no redundancy: there's no fault tolerance, and once damaged, it can lose data permanently. A NAS configured with RAID 1, 5, 6 or 10 can withstand one or more drive failures, depending on the configuration.
• RAID has a capacity cost. One guide notes that RAID 10 cuts usable capacity in half because data is mirrored across pairs of drives.
• RAID isn't a backup. Seagate's support documentation says a second physical copy can live on an external drive, a NAS or a cloud service. It also warns that RAID isn't a self-contained backup. Another guide spells out the risk: after a power outage, a hack, or ransomware that encrypts your files, RAID will simply replicate the error across all disks.
• Automated backups depend on the product. Synology's Hyper Backup, for example, can back up to local volumes, external devices, other Synology systems, rsync servers, or public clouds such as Google Drive. It supports scheduling and multiple versions. That supports the claim that certain NAS products offer automated backup tools. It doesn't mean every NAS has them, or that they're switched on by default.
• External drives can still play a role. Disconnected storage has a niche. One guide argues that a powered-off external drive beats a 24/7 NAS for ransomware resistance and mechanical longevity for long-term cold archives. That's one source's view, but it fits the general principle that an offline copy is harder to hit with an attack.

A NAS can also fail, be stolen, lose power, or be hit by accidental deletion or malware. The usual rule of thumb is the 3-2-1 approach: three copies, on two kinds of media, with one off-site. One source notes that a 2TB external HDD paired with a cloud service covers the 3-2-1 backup rule at minimal cost.

Cost: treat the quoted prices with caution​

The original article cites about $90 for a 4TB external drive and "upwards of $200" for a 4TB NAS system. There's no dated price source behind those figures, and it's unclear whether the NAS number includes the drives. Don't treat them as current averages. What holds up is the qualitative point. A NAS usually means an enclosure plus one or more drives, and possibly network upgrades. An external drive is typically a single purchase. Redundancy means buying extra disks, and the cost rises with drive count and capacity.

Which should you pick?​

An external drive suits you if:

• You're one person who wants portable storage or a second local copy of your files.
• You want plug-and-play with no network or RAID to manage.
• You want an offline copy to put away.

A NAS suits you if:

• Several users or devices need shared, always-available storage.
• You want scheduled, automated backups of multiple PCs.
• You're willing to handle setup, permissions, updates and security.
• You want expandable multi-drive storage and tolerance for a drive failure.

Pre-purchase checklist​

1. Check how many drives the NAS supports and whether it has an expansion option.
2. Work out usable capacity under the RAID level you plan to use.
3. Confirm drive compatibility requirements for that model.
4. Look at your network. A 1GbE link, Wi-Fi or a faster wired setup will shape real-world speed.
5. For external drives, check the USB version and cable. The port, cable and drive all limit the speed.
6. Review backup destinations and how you'll secure remote access.
7. Add up the total cost: enclosure, disks, and any network or backup service.

The bottom line​

TechRadar's broad verdict holds up. A NAS is better for shared access in a business, and an external drive is better for casual, portable use. Where it falls short is on speed units, interface-versus-real-world comparisons, unsourced prices and the claim that a NAS is inherently safer. Whichever you choose, plan for an additional copy of anything important, because neither device is a backup strategy on its own.