This SSD speed test measures how fast your computer's drive saves and opens files, whether it is an NVMe SSD, a SATA SSD or a hard drive. Press Start and the tester writes test files to the browser's private storage on this drive, asks the system to commit them to the drive, reads them back, times hundreds of small files and deletes everything. It works in Chrome, Edge, Firefox and Safari on Windows, Mac, Linux and ChromeOS. To test an external SSD or USB drive instead, switch to Folder on a drive in Chrome or Edge, and the same tester doubles as a hard drive speed test for disks in USB enclosures.
How to test your SSD speed
- Close programs that use the drive heavily, such as games installing updates, backups or cloud sync.
- Leave This device selected for the computer's own drive. For an external drive, choose Folder on a drive, press Choose and pick the drive.
- Choose a size. 1 GB is a good start. 4 GB or 16 GB shows whether write speed collapses once the drive's fast SLC cache is full.
- Press Start test and watch the graph: yellow for writing, green for reading.
- For a read that cannot come from memory, press Read speed of a file I choose and pick a large file you have not opened since the computer started, such as an old video or a game file.
What the results mean
| Readout | What it measures | SATA SSD | NVMe SSD | Hard drive |
|---|---|---|---|---|
| Write | Saving large files, MB/s | 350 to 520 | 1,000 to 6,000 | 80 to 220 |
| Read | Opening large files, MB/s | 400 to 550 | 1,500 to 7,000 | 80 to 250 |
| Small file writes | 4 KB files saved per second | 200 to 1,500 | 300 to 3,000 | 30 to 150 |
| Copy a 4 GB file | Time to save one 4 GB file | About 10 s | 1 to 4 s | 20 to 50 s |
On this device the tester asks the system to push each 32 MB of data to the drive before it stops the clock, so the write figure reflects the drive and not your memory. Small file writes are each committed to the drive one at a time, the slowest pattern there is, which is why they separate hard drives, SATA and NVMe so clearly.
Typical SSD and hard drive speeds
| Drive | Interface limit | Best large file speeds |
|---|---|---|
| Laptop hard drive, 5,400 rpm | SATA, 600 MB/s | 80 to 140 MB/s |
| Desktop hard drive, 7,200 rpm | SATA, 600 MB/s | 150 to 280 MB/s |
| SATA SSD | SATA, 600 MB/s | 500 to 560 MB/s |
| NVMe SSD, PCIe 3.0 x4 | About 3,900 MB/s | Up to 3,500 MB/s |
| NVMe SSD, PCIe 4.0 x4 | About 7,900 MB/s | Up to 7,450 MB/s |
| NVMe SSD, PCIe 5.0 x4 | About 15,700 MB/s | Up to 14,000 MB/s or more |
Hard drives are fastest at the start of the disk and slow down by roughly half toward the end, so a nearly full hard drive tests slower.
Write speed drops partway through the test
A graph that runs high and then falls to a much lower level shows the drive's SLC cache running out. Most consumer SSDs write the first few GB into a fast cache, then write straight to slower memory. Drives with QLC memory can drop to 100 to 200 MB/s, slower than a SATA SSD. This is normal behavior, but it is what you will see when copying very large files. Choose 16 GB to find where the drop happens, and keep at least 15 to 20 percent of the drive free, because the cache shrinks as the drive fills.
A drop that comes and goes in waves, often after a minute or two, is heat. NVMe drives slow down near 70 to 80 °C to protect themselves. A heatsink on the drive or better case airflow fixes it. In a laptop, check the laptop overheating guide, since a hot CPU cooks the SSD next to it.
The SSD is slower than its rating all the time
- The M.2 slot. Some boards run a second or third M.2 slot through the chipset or with two PCIe lanes instead of four, or at PCIe 3.0. Check the motherboard manual and move the drive to the slot wired to the CPU. CrystalDiskInfo shows the link in its Transfer Mode field, for example "PCIe 4.0 x4".
- An M.2 SATA drive. M.2 drives come in SATA and NVMe types that look alike. An M.2 SATA SSD is capped near 550 MB/s.
- SATA mode. In the BIOS, SATA drives should run in AHCI mode, not IDE. Switching it after Windows is installed can stop Windows from starting, so follow your board maker's steps.
- Old firmware. Download the maker's tool, such as Samsung Magician, Kingston SSD Manager or Sandisk Dashboard (formerly WD Dashboard), and update.
- A nearly full drive. Free up space, then on Windows open Defragment and Optimize Drives and press Optimize, which sends TRIM to an SSD.
Hard drive speed test results
A healthy desktop hard drive writes and reads large files at 150 to 250 MB/s, but small files at only dozens per second, because the head has to move for each one. That is normal and is why moving Windows to an SSD makes a computer feel so much faster. Warning signs are speeds well below 80 MB/s on a desktop drive, a graph that dips sharply at random points, and clicking or grinding sounds. Check the drive's health with CrystalDiskInfo on Windows or sudo smartctl -a /dev/sda on Linux, and copy your files off a drive that reports reallocated or pending sectors. Some large hard drives use SMR recording, which writes quickly at first and then drops to a crawl during long copies.
Testing SSD speed on Windows 11, Mac and Linux
- Windows 10 and 11: CrystalDiskMark is the standard free benchmark. Without installing anything, run
winsat disk -drive Cin Terminal as administrator. - Mac: Blackmagic Disk Speed Test and AmorphousDiskMark are free in the App Store. System Information lists NVMe drives under NVMExpress, with their link speed and width where the Mac reports them.
- Linux: GNOME Disks has Benchmark Disk in its menu. In a terminal,
sudo hdparm -t /dev/nvme0n1gives a quick read figure, and fio runs every kind of test.
External SSDs depend on the USB link as much as the drive: the usb speed tester explains which ports and cables reach which speeds, and the sd card speed tester covers memory cards. If the whole computer feels slow rather than just file copying, the ram test and cpu stress test check the other two usual suspects.
What a browser cannot measure
A browser tests drives through ordinary files, so it cannot run the high queue depth tests behind the headline figures on an SSD's box, and very fast NVMe drives hit the browser's own limit before their own. The read figure in This device mode may partly come from memory, and the small file figures include the browser's work per file. For lab grade numbers use CrystalDiskMark, AmorphousDiskMark or fio. For everyday questions, such as whether the drive is SATA or NVMe speed, whether it slows down on long copies, or whether a hard drive is failing, this test answers them in a minute.
SSD speed test questions
What is a good SSD speed?
A SATA SSD reads and writes at about 500 to 550 MB/s. An NVMe SSD on PCIe 3.0 reaches up to about 3,500 MB/s, PCIe 4.0 up to about 7,000 MB/s and PCIe 5.0 over 10,000 MB/s. A hard drive manages 80 to 250 MB/s. Through a browser, expect somewhat lower figures than these lab numbers.
How do I test SSD speed on Windows 11?
Run this test in Chrome or Edge, or install CrystalDiskMark, the standard free benchmark. Without installing anything, open Terminal as administrator and run winsat disk -drive C for sequential and random figures.
Why is my new SSD slower than advertised?
Advertised speeds are best case reads at high queue depth. Real slowdowns come from a full SLC cache during long writes, heat, an M.2 slot with fewer PCIe lanes, a SATA port set to IDE mode, or a drive that is nearly full. The sections above cover each one.
Is this hard drive speed test safe?
Yes. It writes only its own test files to the browser's private storage or to the folder you pick, and deletes them at the end. It never reads or changes your files, and nothing is uploaded.
Why does the read speed look too high?
Your system keeps recently written data in memory, so reading it back straight away partly measures memory. For a cold read, press Read speed of a file I choose and pick a large file you have not opened since the computer started.
Can I test an SSD speed online on a Mac?
Yes. The This device test works in Safari, Chrome, Edge and Firefox on a Mac. To test an external SSD by picking a folder, use Chrome or Edge.