CrystalDiskMark is a storage benchmarking utility. This application is designed to benchmark the performance of read and write operations for storage disks in a computer. It works by continuously reading and writing precisely sized chunks of data to and from individual storage disks.

Because most drives have an expected level of performance, CrystalDiskMark can be used to diagnose issues, too. For instance, if your computer or server feels sluggish, running CrystalDiskMark is an excellent way to help narrow down where that issue might be. Likewise, if you have a NAS with poor performance issues, CrystalDiskMark is a perfect way to see if those performance issues start at the network or physical computer hardware level.

CrystalDiskMark is also a great way to measure capacity in enterprise environments. For example, let’s say that you need to deploy a new application, but that application requires a certain number of IOPS. How do you know if your storage solution is fast enough for that application? You can benchmark it using CrystalDiskMark.

CrystalDiskMark is free. And if you happen to be a fan of anime, you can choose an anime-themed skin for the application.

Why Do Hard Drives Have Different Speeds?

Before we dive into explaining how to read the CrystalDisk benchmark info, it’s important to understand how hard drives work and what impacts their performance.

There are two primary types of storage drives:

  • Mechanical spinning hard drives
  • Solid-state drives

Mechanical drives are much slower than solid-state drives. That’s because mechanical drives have moving components. Mechanical drives store data on a platter similar to a vinyl record, and a floating head reads that data much like a record player needle. But, just like a record, data from a mechanical drive can’t be read until the platter spins into position. So, mechanical drives are limited by how much data that head can read at one time and how quickly its platters spin.

On the other hand, solid-state drives don’t have those limitations. Data on a solid-state drive is stored in banks of capacitors. Those banks can be accessed very quickly. But, this is an oversimplification of how solid-state drives work. They use a variety of technologies, too, so performance can vary widely among them.

Finally, we need to discuss block sizes. Understanding block sizes is essential for understanding how CrystalDiskMark works. Storage devices store data in blocks. Filesystems designate how large those blocks are. That block size can be tweaked to maximize storage space or performance. Think of these blocks like cargo containers. Each cargo container can hold a specific amount of stuff. Those cargo containers are then stored in a storage yard or on a container ship. Those storage yards or container ships hold the same amount of storage containers whether they’re filled or not. They have space for only so many containers. It’s the same for hard drives. They can only hold so many blocks.

These block sizes are tiny. They’re measured in bits. For the sake of easy math, let’s say that a single storage block holds eight bits of data (not accurate, but easy to understand). Let’s say that you save a document to your storage drive that is 12 bits in size. That document is going to use two blocks for storage or a total of 16 bits. Thus, 16 bits of storage are used on your drive even though that document is only 12 bits in size.

How Do You Use CrystalDiskMark?

To read the CrystalDiskMark benchmark info, first, you’ll need to learn how to run CrystalDiskMark. Fortunately, CrystalDiskMark is an easy application to learn.

First, download CrystalDiskMark. After downloading and installing the application, launch it. If you’re using an NVME drive, change the option from Default to NVME in the Settings menu.

Next, choose which disk you want to benchmark from the drop-down menu at the top of CrystalDiskMark. Finally, make sure there’s plenty of free space on the drive you want to benchmark. CrystalDiskMark requires some free space to be available.

How Do You Determine How Much Free Space You Need on a Drive to Run CrystalDiskMark?

You’ll see a menu for test size to the left of the drop-down menu to select a drive to benchmark. That setting defaults to 1Gb. In practice, it’s wise to have double the amount of space needed for the benchmark available on the drive you’re testing.

Finally, click the All button to start the hard drive benchmark. After a few moments, CrystalDiskMark will display the results.

How to Read the CrystalDisk Benchmark Info

The first line of data in CrystalDiskMark is a sequential test that uses a 1MB file with a queue depth of eight and a thread count of one. This test best matches advertised speeds typically. However, this test is more of a theoretical test. The second data line is another sequential test that uses 128KB files with a queue depth of 32 and one thread. This test better represents real-world usage.

Sequential read benchmarks test how long it takes to read or write data into sequential blocks on the drive. In real-world usage, this would be like saving a video to a hard drive. Sequential read and write operations will always be faster than random operations.

The third line is a random test that uses a 4KB file with a queue depth of 32 and 16 threads. Finally, the last test is another random test that uses a 4KB file with a queue depth of one and one thread.

Random read and write operations are typically much slower on all storage devices. Still, mechanical spinning drives are impacted the most by these types of operations. That’s because spinning drives must wait for platters to rotate before the next chunk of data can be found and read. This is also called seek time. Most solid-state drives have an order of magnitude faster seek times than mechanical drives.

The first number in each column is read speeds and the second number represents write speeds.

Queue depths are the number of files waiting in line to be either read or written to a drive. For example, SATA mechanical drives have a max depth of 32, while NVME drives have an upper limit of 65,000.

Finally, processes are the number of different applications requesting attention from a drive. The deeper the queue depth and the more threads acting on a drive, the worse performance it will have.