H2testw is a lightweight, free software tool used to verify whether your USB flash drive, SD card, or external hard drive is working properly. Many users rely on this tool to identify fake storage or detect hardware damage.
One of the most common questions users ask is: How long does it take for H2testw to complete a test? This time depends primarily on the storage capacity and read/write speed of the device being tested.
Why Does It Take So Long?
H2testw is thorough because it performs two distinct phases:
- Writing Phase: It fills the entire drive with data.
- Verifying Phase: It reads that data back to ensure it wasn’t lost or corrupted.
Because it touches every sector of the drive, a 64 GB pen drive may take 20-25 minutes, while a 1 TB microSD card may take several hours or even days if the card is slow or fake.
Estimated Test Times
The time required varies based on the “Class” of your device and the USB port version you are using.
| Capacity | Estimated Time (Fast/Original) | Estimated Time (Slow/Fake) |
| 8 GB | 5 – 15 minutes | 30+ minutes |
| 16 GB | 10 – 25 minutes | 1 hour+ |
| 32 GB | 15 – 45 minutes | 2 hours+ |
| 64 GB | 30 – 90 minutes | 4 hours+ |
| 128 GB | 1 – 3 hours | 8 hours+ |
| 512 GB | 4 – 10 hours | 24 hours+ |
| 1 TB+ | 8 – 20 hours | 2+ days |
If your test is taking dramatically longer than expected, the device may be fake or defective.
What Slows H2testw Down?
If the test feels unusually slow, one of these bottlenecks is usually responsible:
- Slow Hardware: Cheap or counterfeit cards use low-quality flash memory with poor write speeds.
- Legacy USB Ports: Using a USB 2.0 port instead of USB 3.0/3.1 will strictly limit your speed to roughly 30 MB/s.
- System Performance: If your computer is busy with other heavy tasks, the data transfer rate may drop.
- Hardware Failures: Damaged or aging drives will often “hang” or slow down as the tool encounters bad sectors.
How to Speed Up the Test?
While you can’t eliminate the full write/read process, you can optimize conditions:
- Use High-Speed Ports: Always plug into a USB 3.0 (blue) or USB 3.1 port.
- Use a Reliable Reader: For SD cards, use a high-quality USB 3.0 card reader rather than a built-in laptop slot, which can sometimes be slower.
- Close Background Apps: Ensure your PC isn’t running heavy software during the test.
- Test a Sample: If you don’t need full verification, you can select “Only followed megabytes” to test a smaller portion, although this won’t reliably detect “fake capacity” scams.
Is the Wait Worth It?
Yes, if you’re using the drive for essential backups, photos, or videos, it’s best to wait until the test is complete. For years, H2testw has been the gold standard for detecting “ghost” capacity, where a drive claims to have 512 GB but actually only has 16 GB.
Performing this test immediately after purchasing a new drive online can help you avoid permanent data loss later.
Final Words
The rule is simple: the larger and slower the device, the longer the wait. For modern, high-speed 64 GB or 128 GB cards, the process typically finishes within an hour. For larger cards, we recommend letting the test run overnight to ensure your device is 100% reliable.