Does your USB-C cable carry data, and how fast?

Every USB-C cable charges. Not every one carries data, and the ones that do run at very different speeds: 480 Mb/s for USB 2, 5 or 10 Gb/s for USB 3, 40 Gb/s and more for USB4 and Thunderbolt. The plug is the same on all of them, and so, often, is the price.

The quickest way to know is to ask your Mac. Plug the phone in, open System Information, select USB and read the phone's Link Speed. That number is what the phone, the cable and the port agreed on, and it is the ceiling for any copy you make. The rest of this page explains how to read it, and what the markings on a cable do and do not tell you.

Three kinds of USB-C cable

Charge-only cables

These have the power wires and nothing else. The phone charges, and as far as the Mac is concerned nothing is plugged in. No app can see the phone through one, which makes them the first suspect whenever a phone will not show up. They look like any other cable, so the only reliable test is to try one.

USB 2 cables

These carry data at USB 2 speed, 480 Mb/s, over one pair of data wires. They are very common, including from the big names. Apple's 240W USB-C Charge Cable, the woven one sold for charging MacBooks, transfers data at USB 2 speeds, according to Apple's own listing. It charges at up to 240 watts and still copies at USB 2 rates. A cable's wattage says nothing about its data speed.

USB 3, USB4 and Thunderbolt cables

These add more pairs of wires for SuperSpeed data: 5 Gb/s, 10 Gb/s, or 20 Gb/s for USB 3, and 40 Gb/s or 80 Gb/s for USB4. A Thunderbolt 4 cable also carries USB 3 data at 10 Gb/s, so it works for a phone. Any of these is more than a phone needs.

Reading the markings

Cables certified by the USB Implementers Forum carry a logo that states the speed in plain numbers: USB 5Gbps, USB 10Gbps, USB 20Gbps, USB 40Gbps or USB 80Gbps, often beside a wattage such as 60W or 240W. A USB 2 cable may carry the Hi-Speed USB logo instead, which, despite the name, is the slow one. Thunderbolt cables carry a lightning bolt, often with the version number.

Older names still turn up on packaging: USB 3.2 Gen 1 is 5 Gb/s, Gen 2 is 10 Gb/s and Gen 2x2 is 20 Gb/s. A USB-A plug marked SS, for SuperSpeed, is USB 3.

Plenty of cables are not certified and print whatever they like, or nothing. Treat an unmarked cable as USB 2 until your Mac says otherwise.

Ask your Mac: System Information

The markings tell you what a cable should do. System Information tells you what is actually happening.

1. Plug the phone straight into the Mac, with no hub in between.
2. Unlock the phone, and give the Mac something to talk to: choose File transfer in the phone's USB notification, or have USB debugging turned on. A phone that is only charging may not show up at all.
3. Hold the Option key, open the Apple menu and choose System Information. Without the Option key, it is under System Settings > General > About > System Report.
4. In the sidebar, under Hardware, select USB. Find the phone in the list. It may appear under its model name, its maker's name or an internal code name.
5. Read the Link Speed line. Older versions of macOS show Speed instead, as in "Up to 480 Mb/s".

480 Mb/s means USB 2. 5 Gb/s or 10 Gb/s means USB 3. If the phone is not in the list at all, in any USB mode, the cable is probably charge-only or the port is at fault, and Android phone not showing up on Mac covers what else to check.

The link runs at the speed of its slowest part, and there are four: the phone's port, the cable, the Mac's port and any hub or dock in the chain. If you see 480 Mb/s where you expected more, change one thing at a time and look again. Not every Mac port is fast, either: the MacBook Neo has one USB 3 port at 10 Gb/s and one USB 2 port at 480 Mb/s.

Phones that are USB 2 behind a USB-C port

A USB-C port on a phone does not mean USB 3 inside it. Many budget and mid-range phones use USB 2 for data. Samsung's Galaxy A56 and Motorola's Moto G (2025), for example, are listed with USB 2.0 ports, while the Galaxy S25 and the Pixel 9a are listed with USB 3.2. On a USB 2 phone, no cable will make copies faster: the phone sets the ceiling.

To check yours, look up its specifications and find the USB line. "USB Type-C 2.0" means USB 2. "USB Type-C 3.1" or "3.2" means USB 3. Or plug it in with a cable you trust and read System Information, which settles it in a minute.

What speed to expect

USB 2 is 480 Mb/s on paper, which is 60 MB/s before anything else takes its share. In practice, a USB 2 phone or cable holds any method to about 20 to 40 MB/s. A 4 GB video then takes between about two and three and a half minutes, and 100 GB of photos and videos somewhere between 40 minutes and an hour and a half.

USB 3 is in a different class. Over a USB 3 cable, SideMount moves large files at well over 100 MB/s. Whatever you use, the cable stops being the limit: the phone, the app and the files themselves set the pace.

One thing no cable fixes: many small files move far more slowly than one large file of the same total size, with any method, because each file costs a little time to open, create and close. A folder of thousands of tiny files will always crawl compared with a single video.

If the phone is USB 3 and the Mac reports 10 Gb/s, the cable is not your problem. SideMount mounts the phone as a volume in Finder over that cable, and the setup guide covers the first connection. Every way to move files between Android and a Mac compares the other routes.

Questions