SSD vs HDD: What’s the difference?

HDDs are traditional storage devices with spinning platters that read and write data. SSDs use newer technology that stores data on instantly accessible memory chips. SSDs are faster, quieter, smaller, consume less energy, and more durable. HDDs are cheaper, have more storage capacity, and offer easier data recovery if damaged.

Until the late 2000s, when you bought a new hard disk drive or personal computer, your hard disk storage choices were limited to size and speed — perhaps 5,400 or 7,200 rotations per minute. Today, when you buy a new PC, you have two very different options: you can get one with an SSD or one with an HDD.

The laptop on the left above comes with a traditional hard disk drive, while the one on the right has a more modern solid state drive. While SSDs and HDDs are both storage devices, the way they work is quite different.

• HDDs: In an HDD, an enclosure contains a series of platters covered by a ferromagnetic coating. The direction of the magnetization represents the individual bits. Data is written and read by a fast-moving head, similar to the way vinyl record albums work.

  Since all of these pieces are “mechanical,” the hard disk is the slowest and most fragile component of any computer.

• SSDs: SSDs are newer types of disks that store information on flash memory, which consists of individual memory cells storing bits that are instantly accessible by the controller. Learn all about SSDs here.

Why are SSDs useful for laptops?

SSDs are often used in laptops because they’re non-mechanical. Solid state drives require less power, which translates into better battery life. While lower-priced laptops still come with traditional, cheaper hard drives, most mid-range to high-end machines come with an SSD.

While hard disks have moving parts, solid state drives are shock-resistant. If you drop your laptop while the read/write head of a hard drive is in motion — which it usually is — it could result in data failure. This doesn’t happen with SSDs.

But it isn’t always an either/or choice. “Hybrid” computers have both drive types — the operating system (OS), apps, and the most-used files are installed on an SSD, while other data sits on an HDD, which is typically larger and less expensive. Using your SSD to run your OS and apps is a great way to increase SSD performance.

How much faster are solid state drives compared to hard disk drives?

The speed difference between solid state drives vs hard disk drives is significant. SSDs are extremely fast in all areas, but the speed difference is more pronounced when performing certain tasks, such as:

• Sequential read/write operations: The speed difference of an SSD vs hard drive is most apparent when copying and moving huge files. HDDs can copy 30 to 150 MB per second (MB/s), while standard SSDs perform the same action at speeds of 500 MB/s. Newer NVME SSDs can even show speeds of up to an astounding 3,000 to 3,500 MB/s.

  With an SSD, you can copy a 20 GB movie in less than 10 seconds, while a hard disk would take at least two minutes. Upgrading your Mac to an SSD or installing an SSD in your PC will give it a significant speed boost.

• Small 4K read/write operations: Most of the time, when you run your OS, open basic programs, or browse the web, you’re actually opening and manipulating thousands of smaller files, which are stored in small blocks of data (usually sized at 4K).

  The faster your disk can read and write these 4K blocks, the faster and snappier your system operates. With HDDs, the speed ranges from 0.1 to 1.7 MB/s. SSDs and NVME SSDs operate at much faster speeds of 50 to 250 MB/s.

To demonstrate the speed difference between an HDD vs SSD, compare the benchmarks below (we used CrystalDiskMark). The numbers on the left are from a seven-year-old HP 630 laptop. On the right, we’re using a newer 2017 MacBook Pro running Windows 10 with an NVME SSD.

Speed differences between an older HP laptop with an HDD (left) and a newer MacBook Pro with an SSD (right).

SSD speed

On our Mac with an SSD, sequential reads are nearly 56 times faster and small 4K read operations are about 226 times faster. Windows takes just 10 seconds to boot, and there is no visible delay when launching Chrome — it’s just there. Upgrade to an SSD if you want to speed up your Mac or make your PC faster.

HDD speed

In our tests, the HP computer with an HDD was painfully slow. Booting Windows took a full four minutes, and Chrome launched in 15 seconds — longer than it took our SSD computer to start up. Nearly every click in Windows is accompanied by a massive delay.

Whether you’re using an SSD or HDD, you’ll want to make sure it stays clean, so that your machine can operate at its best. Avast Cleanup will tune up your drive, update your apps, and fix other annoying problems, freeing up your computer to run as fast as it should