USB & SD Speed Test
Write and read test
Pick the USB drive or SD card in the window that opens (any folder on it). A test file is written, read back and deleted.
Use 1 GB or more for a fair result. With smaller sizes the computer may hold the data in memory first, which looks faster than the drive really is.
Reading right after writing can come partly from the computer’s memory and look faster. For the real read speed, use the read test.
Read test (any browser)
Pick a large file from the drive, like a video of 500 MB or more that you haven’t opened recently. Only the speed is measured. The file isn’t changed or uploaded.
Choose a file to readWhat the speed means
- < 10 MB/sSlow: a USB 2.0 drive, an old card, or a fake drive.
- 10–40 MB/sBasic: USB 2.0 at its best, or a simple USB 3 drive. Class 10 cards land here.
- 40–150 MB/sGood: a USB 3 drive or a U3 / V30 card, fine for 4K video.
- > 150 MB/sFast: a quality USB 3.1 / 3.2 drive or an external SSD.
A USB 3 drive in a USB 2 port (usually black inside) is limited to about 35 MB/s. Try a blue port or USB-C.
Your own files on the drive aren’t touched. The test uses one separate file and deletes it at the end, so it needs that much free space.