How to compare a card reader with a camera's USB

Your camera may take longer to copy photos than a card reader does, but that does not automatically mean the camera or card is faulty. The reader, camera, USB cable, connection mode, and computer port can all affect the result.

To make a useful comparison, test the same card through both connections under similar conditions. The USB & SD Speed Test can measure a card that the browser can access as a drive. If the camera does not appear as a drive, you can still compare actual file transfers, but that is a different kind of test.

Compare the card reader and camera

1. Open the USB & SD Speed Test and connect the memory card through the card reader. Follow the on-screen prompt to select the card if it is offered. Back up important files first, because a speed test writes data to the card.
2. Run the test and write down the read and write results. Read speed is how quickly data comes from the card. Write speed is how quickly data is saved to it. Keep the units shown by the test, such as MB/s, when you make notes.
3. Safely eject the card, put it in the camera, and connect the camera to the same computer using the same USB port. Use the camera's USB connection setting for data transfer, if it has one.
4. If the camera connection appears as a drive that the test can access, run the test again and note both results. Keep the same card and computer port, and avoid using other apps that are copying large files during either test.
5. If the camera does not appear as a drive in the test, do not treat that as a failed speed test. Instead, copy the same large video or photo file from the card to the computer once through the reader and once through the camera, timing each transfer. Only try copying back to the camera if it normally accepts files that way.

For a more reliable comparison, repeat each measurement two or three times and look at the typical result rather than the single fastest run. Use a file large enough that the transfer takes several seconds, so a brief pause at the start does not dominate your timing.

What the results mean

The card reader is faster than the camera

This is common. The camera may use a slower USB connection, a slower card interface, or a photo-transfer mode that adds overhead. If the camera presents photos through a transfer protocol rather than as a normal drive, copying through it may be slower than reading the card directly. That does not prove the camera is defective.

The camera and reader give similar results

The camera's connection is probably not limiting transfers much in this setup. The card itself, the computer's USB port, or the test conditions may be setting the pace. Small differences between runs are normal, especially if other tasks are using the computer or storage.

Both connections are slower than expected

The card may be slow, but check the shared parts of the setup before blaming it. A USB hub, an older port, a slow reader, or a cable can limit both tests. Also check that the speed you are comparing is the card's real read or write speed, not a number printed on its packaging. Advertised maximums are not guaranteed results.

The camera does not show up in the test

Many cameras offer photos through a camera-transfer mode instead of exposing the memory card as a drive. A browser tool that tests a removable drive cannot measure that connection in the same way. On Windows 11, look in File Explorer › This PC for a drive. On macOS, check Finder › Locations, or use Image Capture to import photos. If the camera appears only as a camera or photo source, use a timed file transfer to compare the real workflow.

How to get a fairer comparison

1. Use the same card and port. Keep the card, computer, and USB port the same between tests. A different port can have a different speed or may share bandwidth with other devices.
2. Connect the reader directly. Remove the hub or dock for the test. If you normally use a hub, you can run a separate test through it afterward. See why external drives can slow down through USB hubs.
3. Check the camera's USB mode. Look in the camera's setup or connection menu for a data-transfer option. Some cameras offer a storage mode, while others use a camera or photo-transfer mode. The names and choices differ by model, and some cameras do not offer storage mode.
4. Try a known data cable. Some USB cables are made only for charging. Use a cable that transfers files, connect it firmly, and try another USB port if the camera disconnects or is not recognized.
5. Check the card and reader limits. A fast card cannot exceed the speed supported by the reader or camera. If your card or reader supports different interface versions, the slower compatible connection sets the practical limit.
6. Close other transfers and let the camera stay awake. Stop cloud uploads and large downloads while testing. Keep the camera powered on and prevent it from entering sleep during a timed transfer.

Why a camera transfer is not always an apples-to-apples test

A card reader usually gives the computer direct access to the memory card. A camera can instead manage which photos are visible and how they are sent. That camera-managed transfer includes work beyond reading the card, so its time may not match a direct card speed measurement.

The card reader test is useful for checking the card-and-reader combination. A timed copy through the camera answers a different question: how quickly can you move files using the camera's normal connection? Compare like with like, and use the method that matches how you actually transfer your photos.