SSD vs HDD: Which Storage Should You Choose?

If your computer takes ages to boot, apps hang for a few seconds before opening and file searches crawl, there’s a good chance it’s running on a hard drive. Swapping it for a solid-state drive is often the single biggest speed upgrade you can make. But hard drives haven’t disappeared, and for some jobs they’re still the smart choice.

This guide compares SSDs and HDDs on speed, durability and cost per gigabyte, explains the different types of SSD you’ll see when shopping, and shows the best use for each.

How SSDs and HDDs work

A hard disk drive (HDD) stores data magnetically on spinning metal platters. A read/write head on a moving arm hovers over the surface to find each piece of data. Because the drive has to physically spin and move the arm into position, there’s a delay every time it looks for something.

A solid-state drive (SSD) stores data on flash memory chips with no moving parts. A controller reads and writes data electronically, so it can reach any file almost instantly.

That one difference, moving parts vs no moving parts, explains nearly everything else in this comparison.

The quick comparison

Key takeaway: Use an SSD for anything you work with every day, and a hard drive only for large amounts of data you rarely need quickly.

Speed: where SSDs win by a mile

Speed is the biggest difference, and it shows in 2 ways.

Sequential speed is how fast a drive moves large files, like copying a video. Manufacturer data sheets show the gap clearly. Seagate’s data sheet for current 7200 RPM BarraCuda desktop hard drives lists a maximum sustained transfer rate of 190 MB/s. SATA SSDs are capped by the SATA interface at roughly 600 MB/s. NVMe SSDs on PCIe are much faster: Samsung rates its 990 PRO, a PCIe 4.0 drive, at up to 7,450 MB/s for sequential reads. That’s dozens of times the hard drive’s figure.

Random access is how fast a drive finds lots of small pieces of data scattered across it, which is what happens when your computer boots, opens apps or searches files. Here the gap is even bigger, because a hard drive has to physically move its head for each request. This is why a computer moved from an HDD to an SSD feels so dramatically faster, even for simple tasks.

Note that manufacturer speeds are “up to” figures measured under ideal conditions. Real-world speed depends on your computer, the file sizes and how full the drive is.

Types of SSDs you’ll see when shopping

Not all SSDs are the same. Here’s how to read the labels.

For a new PC, an M.2 NVMe drive is the default choice. Check your motherboard or laptop manual for which slots support which PCIe generation. A faster PCIe 5.0 drive in a PCIe 4.0 slot will work but at the slower slot’s speed. Our step-by-step guide on how to build a PC shows where the drive goes.

Durability and reliability

Physical durability

SSDs have no moving parts, so they handle drops, bumps and vibration far better, which is one reason virtually every modern laptop uses one. A hard drive dropped while it’s spinning can suffer a head crash and lose data.

Failure rates

You might assume SSDs are far more reliable overall. The data is more nuanced. Backblaze, a cloud storage company that publishes failure statistics from its large fleet, compared SSDs and HDDs used as boot drives in its servers. Once it matched the drives by age, it concluded that SSDs failed less often, but not by much, and that the difference alone wasn’t enough to justify choosing one over the other. Its advice: decide based on other factors like speed, cost and power use.

Wear and endurance

SSD flash cells wear out after a very large number of writes. Manufacturers publish an endurance rating called TBW (terabytes written). Samsung, for example, rates the 1TB 990 PRO at 600TB written, with a 5-year limited warranty, whichever comes first. For typical home and office use, you’re unlikely to approach these limits during the drive’s useful life. Heavy video editors and people running servers should check TBW ratings.

Long-term storage without power

SSDs aren’t ideal as unpowered archives left in a drawer for years. Data retention on flash memory declines over time without power, and faster in hot conditions. Hard drives also degrade, which is why no single drive should be your only copy.

Whatever you choose, back it up. Our guide on how to back up business data explains the 3-2-1 backup rule, and how to back up your photos covers personal libraries.

Cost per gigabyte

Hard drives are still much cheaper per gigabyte, and the gap is largest at high capacities. If you need many terabytes, such as a family’s video archive, a home media server or a business NAS, hard drives give you the most space for the money. Prices for both change frequently, so compare cost per terabyte at the time you buy rather than relying on old figures.

SSD prices have fallen dramatically over the years, which is why even budget laptops now ship with SSDs. For the capacities most people need on their main drive, 512GB to 2TB, the price premium is easily worth the speed.

Best uses for each

Choose an SSD for

• Your main drive in any laptop or desktop, holding the operating system and apps
• Games, which load much faster
• Active creative projects, like video you’re editing now
• Laptops, for speed, battery life and drop resistance
• External drives you travel with

Choose an HDD for

• Backups of your computer, especially local backups that sit alongside cloud backups
• Media libraries of photos, videos and music you don’t edit often
• NAS and home servers that need many terabytes
• Security camera recordings on network video recorders built for them
• Archives that are accessed occasionally

Use both together

Many desktops use an SSD for the operating system and apps plus a large HDD for bulk files. That gives you speed where it matters and cheap space for everything else. Cloud storage can also take the place of a bulk drive; compare options in iCloud vs Google Drive vs OneDrive.

Where to start: picking the right storage

1. Make your main drive an SSD. If your current computer still boots from a hard drive, upgrading to an SSD is one of the most cost-effective speed boosts available.
2. Pick the capacity. 512GB suits most office and school users, and 1TB to 2TB suits gamers, creators and anyone keeping large files locally. On laptops where storage can’t be upgraded, buy what you’ll need for its whole life.
3. Match the interface. Check whether your computer takes M.2 NVMe, M.2 SATA or 2.5-inch SATA drives, and which PCIe generation its slots support.
4. Add an HDD or cloud storage for bulk files and backups if you need several terabytes.
5. Set up backups before you need them. A drive of either type can fail.

If you’re also deciding on memory, our guide on how much RAM you need pairs well with this one, and our laptop buyer’s guide brings all the specs together.

Conclusion

The SSD vs HDD choice is simpler than it looks. For your main drive, choose an SSD every time: it’s dramatically faster, quieter, tougher and more power-efficient. Hard drives still earn their place for backups, media libraries and anything that needs lots of cheap space. Use each where it’s strongest, keep backups of everything, and your storage will be fast and safe. For definitions of terms like NVMe and TBW, see our glossary.

Sources

• Samsung: 990 PRO data sheet — sequential read speed, TBW endurance and warranty terms
• Seagate: BarraCuda 3.5-inch HDD data sheet — 7200 RPM hard drive sustained transfer rate
• SATA-IO: SATA 6Gb/s white paper — SATA Revision 3.0 interface speed of 6Gb/s
• Backblaze: Are SSDs really more reliable than hard drives? — age-matched SSD and HDD boot drive failure comparison