Test storage speed during a backup on a fanless PC

Your backup starts quickly, then slows down, or the mini PC seems to bog down while it runs. On a fanless computer, heat can build up during sustained work, but the backup destination, USB connection, and other apps can also affect the speed.

Use the Storage Test to compare browser storage performance before and during a backup. Treat it as a comparison, not a verdict on the backup drive: the test cannot measure every part of the backup process.

Compare storage speed before and during a backup

1. Open the Storage Test before starting the backup. Close unnecessary apps and keep the mini PC in its usual position, with its vents unobstructed.
2. Run the test and note the large-file speed, small-write speed, and score. The tool measures both types of storage work, which can respond differently to a busy drive.
3. Start your regular backup. Note the backup app's reported speed after it has settled, rather than comparing a brief startup burst. Keep the same files, destination, and connection you normally use.
4. If the backup is stable and you can safely tolerate a brief slowdown, run the Storage Test again while it is active. Note the time and results. The test adds storage work, so it may temporarily slow the backup. If the copy is important or already struggling, wait until the next backup instead.
5. When the backup finishes, run the test once more under the same conditions. If you suspect heat, let the mini PC return to room temperature and repeat it again. Do not unplug the destination while data is being written.

Compare the pattern across runs, not just one score. Keep the computer plugged into its normal power source, use the same browser, and avoid opening other large files during the comparison.

What the results mean

Storage results dip during the backup and recover afterward

The backup is competing for storage access, or the drive is busy handling both the backup and the browser test. A temporary drop is expected when two tasks read or write data at once. If the backup finishes without errors and returns to its usual pace, the dip alone does not show that the drive is failing.

Results decline during the backup and stay low while the PC is warm

Heat may be reducing performance. Fanless computers rely on their case and surrounding air to carry heat away, so a closed cabinet, soft surface, or nearby heat source can make sustained work harder. A browser test cannot read the exact temperature of the processor or drive, so use the timing of the slowdown as a clue, not proof.

The browser test stays similar, but the backup slows down

The slow part may be outside the storage workload measured by the test. A backup can spend time compressing or encrypting files, checking changes, sending data over a network, or waiting for a cloud service. A slow external drive, cable, hub, or destination can also affect the backup without producing the same pattern in a browser test.

Scores change a lot between runs

Other apps, background updates, available space, and the browser's own activity can change results. Close background tasks, wait a few minutes, and repeat the comparison once. A single score is not a reliable diagnosis.

How to reduce backup slowdowns

1. Give the mini PC room to release heat. Put it on a hard, open surface and leave space around its vents and cooling surfaces. Avoid stacking it on a warm drive or placing it inside a closed cabinet during a long backup.
2. Use normal power while testing. On Windows 11, open Settings › System › Power & battery › Power mode and choose a performance mode appropriate for plugged-in use. On a Mac laptop, check System Settings › Battery › Low Power Mode and turn it off for a comparison if available. Many desktop Macs do not show this setting.
3. Connect the backup drive directly if practical. A hub, adapter, or long cable can introduce a slower link or unreliable connection. Try a different port and cable, one change at a time, and compare the backup app's actual progress.
4. Reduce competing work. Pause large downloads, file synchronization, and other backups while you check the normal backup rate. Do not disable security software just to improve a test score.
5. Check the destination and backup settings. Confirm the backup is going to the expected drive or network location and that the app is not verifying, compressing, or encrypting data. Those stages can take longer than copying files alone.

When it may be a hardware problem

A lower browser score during one backup is not enough to condemn a drive. Look for repeated problems: the destination disconnects, files fail to copy or verify, the backup reports read or write errors, or performance remains unusually poor after the workload stops and the computer cools.

Make another copy of important files before investigating a drive that reports errors. Check the drive using the computer's built-in diagnostic tools or ask the manufacturer or a repair shop to inspect it. If the drive disconnects on multiple computers with more than one cable, replacement may be safer than relying on it for backups.

Why the browser test may not match the backup rate

The Storage Test gives a repeatable indication of browser-accessible storage performance, including large-file work and small writes. It is not a direct measurement of your backup app's complete route to a particular destination. The backup may use a network, compression, encryption, or file-by-file checks that the browser test does not reproduce.

Use the backup app's own progress reading to judge the copy itself, and use the browser test to see whether storage performance changes under comparable conditions. Test data and files handled by TooLab tools stay on your device.