External drive slow through a hub? How to test it

Your external drive used to copy files quickly, but it feels slower after you connected a hub. The hub may be sharing bandwidth, providing too little power, or using a slower port. A repeatable comparison can help narrow it down.

Use the USB & SD Speed Test for a USB flash drive or memory card. It is designed to test those storage types. If your external hard drive or SSD is not available to the tool, use the same file-copy comparison described below instead.

Compare the drive through the hub and directly

Open the USB & SD Speed Test and connect the storage device through the hub. Follow the tool's prompts if it can access that device. If it cannot, note that the tool does not support testing your drive in this browser.
Run the test once with the hub connected, then repeat it two more times. Keep the drive, computer, browser, and other connected devices the same. Write down the read and write results separately.
Safely eject the drive, disconnect the hub, and connect the drive directly to the same computer. Use the same cable and port where possible. Run the same test again, or copy the same large file if the tool could not access the drive.
Compare the repeated results, not just the fastest run. A hub-related slowdown is more likely if the direct connection is consistently faster by a clear margin.

For a file-copy comparison, use a single large file and time the same direction of transfer each time. Copying many small files can take longer for reasons unrelated to the hub. Make sure the drive has enough free space, and do not unplug it while data is being written.

What the result means

The drive is consistently slower through the hub

The hub, its upstream cable, or the port it uses may be limiting the connection. A hub shares its connection to the computer among attached devices, so another drive, webcam, or other active device can affect results. Test the hub with other devices disconnected, then check its power and cable.

The results are close, with small changes between runs

Small differences are normal. Background activity, file caching, drive temperature, and the size of the test can all change a result. Repeat the comparison under similar conditions before deciding that the hub is responsible.

The drive is slow both directly and through the hub

The hub is less likely to be the only cause. The drive, its cable, the computer's port, or background activity may be limiting speed. Check the drive directly with another known-good cable or computer if one is available.

The tool cannot access the external drive

This does not mean the drive or hub is faulty. The USB & SD Speed Test is intended for flash drives and memory cards, and browser access to storage varies. Use a consistent file-copy test for an external HDD or SSD instead.

How to fix a slow connection

Disconnect other devices from the hub. Try the drive with nothing else attached, then add devices back one at a time. This can reveal whether another active device is sharing the hub's connection.
Try another port on the computer. Connect the hub to a port on the computer itself, not to another hub or adapter. If the computer has ports with different capabilities, check its documentation to identify a high-speed data port.
Check the cables and connectors. Reseat the hub's cable and the drive cable, then test with a known-good compatible cable. A cable that charges a device may still be unsuitable for high-speed data.
Give the hub and drive enough power. If the hub has a power adapter, connect it. A bus-powered hub gets power from the computer, which may not be enough for a power-hungry drive and other attached devices. Do not use a cable or adapter that does not match the device's requirements.
Connect a laptop to power. A power-saving mode can affect performance on some computers. On Windows 11, check Settings › System › Power & battery. On a Mac, check System Settings › Battery and turn off Low Power Mode for the comparison, if it is enabled.
Check for system updates. On Windows 11, open Settings › Windows Update. On macOS, open System Settings › General › Software Update. Restart after an update, reconnect the drive, and repeat the test.
Compare with a different hub. If the drive is fast when connected directly but slow through this hub, test another compatible hub. For more on common causes, see why external drives slow down through USB hubs.

When the drive or hub may be faulty

If the drive remains slow when connected directly to more than one computer, try another compatible cable and check whether the drive makes unusual noises or disconnects. A mechanical drive can slow down during heavy activity, but repeated errors, clicking, or frequent disconnections are reasons to stop using it and protect any important files. If the drive is under warranty, contact the manufacturer before opening it.

If several drives perform poorly through one hub but work normally when connected directly, the hub or its cable is a stronger suspect. Replace it with a compatible hub, or ask the manufacturer about warranty service.

Why speed can change on the same setup

A hub's advertised maximum is not a promise that every connected drive will reach that speed. The computer port, hub, cable, and drive all need to support the same data standard, and the slowest part can limit the connection. A hub's ports may also share bandwidth through one cable to the computer.

For a useful comparison, keep the setup as similar as possible and look for a repeatable difference. A browser test can help check supported USB flash drives and memory cards, but it cannot diagnose every external drive or prove that a hub is defective on its own.