Large-file write speed changed after an upgrade

Your computer or storage feels different after an upgrade, and now a large-file write test reports a new speed. That change can come from the drive, connection, power settings, or background activity, not only from the new hardware.

Use the Storage Test to check large-file write speed and compare results under the same conditions. The test runs in your browser, so treat it as a practical comparison, not a direct measurement of every part of the storage device.

Compare write speed before and after the upgrade

Open the Storage Test on the computer and storage device you want to check.
Run the large-file test. Note the write speed and score, and check that the test is measuring the intended drive or storage location.
Repeat the test once under similar conditions. Keep the same browser, power mode, drive connection, and other open apps if you are comparing with an older result.
Compare the new reading with your earlier result. A result from a different computer or browser may not be a fair comparison, even if the drive is the same.
If the change is large or the readings vary, wait a few minutes and run the test again. You can also run the small-write test to see whether the change affects both kinds of work.

Write down the date, drive, connection, browser, power mode, and results. That makes it easier to tell whether a later change comes from the hardware or from the test conditions. For more on variable results, see why storage benchmarks vary between browser runs.

What the result means

Write speed is higher after the upgrade

The browser-based test completed its large-file writes faster in this run. The upgrade may have improved the storage path, for example by adding a faster drive, port, or controller. A higher reading does not prove that every file-saving task will be faster, since everyday work can also depend on the app, file size, and other system activity.

Write speed is lower after the upgrade

Something in the current setup is limiting this test, but the result alone does not identify the cause. A drive connected through a slower port or hub, reduced free space, background writes, or a power-saving mode can all affect performance. Check the connection and repeat the test before deciding the new part is faulty.

Write speed is about the same

The test did not show a clear change in large-file writing. The upgrade may not affect this particular workload, or another part of the setup may be the limit. For example, replacing a processor will not necessarily make a storage drive write faster.

Repeated results are far apart

The setup may be changing between runs, or the browser and operating system may be doing other work. Heat can also affect some drives after sustained writing. Close active downloads and file transfers, let the system settle, and compare another pair of runs.

The score out of 100 is useful as part of the test's comparison, not as a universal rating of drive quality or health. A browser test also cannot diagnose physical damage or verify a drive's manufacturer specifications.

How to check a slower result

Check which drive is being tested. Confirm that the test is using the intended internal or external storage, especially if you added a drive or changed your setup. Results from different storage locations are not a before-and-after comparison of the same device.
Reconnect the drive directly. If it is external, connect it to another port on the computer and, if possible, test without a hub or dock. Try a known compatible cable. A connector's shape alone does not guarantee a particular transfer speed.
Pause other storage activity. Wait for downloads, backups, file copies, and system updates to finish, then rerun the test. Close apps that are actively saving large files.
Check free space. Low free space can affect some drives and operating systems. On Windows 11, open Settings › System › Storage. On macOS, open System Settings › General › Storage.
Check the power mode. On Windows 11, open Settings › System › Power & battery and review Power mode. On a Mac laptop, open System Settings › Battery and check whether Low Power Mode is enabled. For a fair comparison, use the same setting for both tests.
Restart and test again. A restart can clear pending updates or a process that was using the drive. After signing back in, wait for startup activity to settle before running the test.
Review the upgrade connection or driver. If you replaced a drive, adapter, dock, or storage controller, check that it is connected as intended and that the manufacturer's current driver or firmware instructions are followed. Avoid changing firmware or drive settings unless you understand the risks and have a backup.

When the drive or connection may be faulty

A speed result by itself is not enough to call a drive broken. Look for other symptoms: the drive disconnects, files fail to save, the computer reports errors, or performance remains unusually poor across repeated tests with a direct connection and no competing activity.

If an external drive shows the same problems on another compatible computer, try a different cable or port before seeking service. If the drive itself continues to disconnect or report errors, back up important files and contact the seller or manufacturer about warranty support. A browser speed test does not check the drive's full health or replace a diagnostic from the manufacturer.

Why large-file speed differs from small-write speed

Large-file writing measures a sustained transfer of bigger chunks of data. Small writes measure many smaller operations, which can behave differently because the drive and system handle them in another way. An upgrade can improve one result without changing the other.

Browser tests also use browser-accessible storage rather than issuing every low-level command available to a dedicated drive diagnostic. The browser, operating system, free space, and cache can influence the number. Use the same machine, browser, storage device, and connection to make the comparison useful. The test uses test data on the device, not your personal files.