H2testw: How to Test SD Card Speed on Windows

H2testw is a simple yet powerful tool developed by Harald Bögeholz, designed for testing the read and write speeds of SD cards and other storage devices via a PC.

Key Benefits of H2testw

• Measures the read and write speeds of flash drives and SD cards
• Verifies whether a flash drive is functioning properly
• Detects read errors and identifies faulty, incorrect, or empty sectors

How H2testw Works

H2testw operates by writing files to all available free space on the storage device, then reading them back to measure performance of a sd card or USB flash drive.

Example report:

Test finished without errors.

Writing speed: 19.9 MByte/s
Reading speed: 21.7 MByte/s

Steps to Test SD Card Speed with H2testw

1. Download H2testw v1.4 from the official website or here:

2. Launch the program.

Note: H2testw doesn't require installation; just run the h2testw.exe file.

3. Select the target directory where you want the files to be written by clicking the "Select target" button.

4. Set the data volume, specifying how much data should be written to the selected location.

5. To check your SD card's speed, click the "Verify" or "Write + Verify" button.

6. See the result and copy to clipboard if needed.

H2testw can test the performance of any storage device connected to your PC, including HDDs, SSDs, USB flash drives, and microSD cards. The key requirement is that your storage device must be properly recognized by your operating system.

Compatibility and Updates

Despite the lack of recent updates, H2testw remains compatible with all modern Windows versions, including Windows 10 and Windows 11.

Frequently Asked Questions (FAQ)

Is It Safe to Use H2testw?

Yes, H2testw is safe to use as it doesn’t require administrative rights and doesn’t overwrite existing data. However, if the hardware is defective, using H2testw might cause issues. In such cases, it’s recommended to format the flash drive before testing.

What Is the Purpose of the Endless Verify Option?

The "endless verify" option is ideal for prolonged testing. It allows H2testw to continuously read and write data for as long as you wish, making it useful for spotting sporadic errors over extended periods.

Can You Trust the Scan Results?

Generally, H2testw provides reliable information regarding the read and write speeds of flash drives and SD cards. However, if the storage device is defective, the results might not be accurate, and the speed readings could be higher than actual performance.