With its desire to simplify everything by encompassing as many standards as possible, USB-C is not far from complicated. If you’ve connected an external USB-C SSD to your Mac using the USB-C cable provided by Apple, you’ve experienced it, there’s something wrong. The storage medium is well recognized by macOS, but transfers are slow, the fault lies with the cable which is only USB 2.0 and therefore cannot exceed 60 MB/s. This cable is not even needed to connect a USB-C monitor.
Image Maurizio Pesce (CC BY 2.0)
There are actually six different types of USB-C cables, all of which look like two drops of water,” says Benson Leung, an expert on the subject:
- USB 2.0 to 3A
- USB 2.0 to 5A
- USB 3.2 Gen 1 (5 Gbit/s) at 3 Amps
- USB 3.2 Gen 1 (5 Gbit/s) at 5A
- USB 3.2 Gen 2 (10 Gbit/s) to 3A
- USB 3.2 Gen 2 (10 Gbit/s) at 5A
One could even add to the list the passive Thunderbolt 3 cables that encompass the whole while additionally handling a 20 Gbit/s throughput with Thunderbolt devices (be careful, active Thunderbolt 3 cables at 40 Gbit/s cannot be used as USB-C cables). Nota bene: USB 3.1 and USB 3.2 are the same, what counts is the suffix “Gen1” or “Gen2” when the speed is not directly specified.
- Thunderbolt 3, USB-C, USB 3.1: what you need to know
So how do you figure it out? First, attach a small label to all USB-C cables in your possession. On Apple’s, for example, indicate “charge – USB 2.0”. For other cables, such as those supplied with Android smartphones or external hard drives, refer to the documentation.
If you can’t find the information, there are mini boxes that can read the characteristics of the cables (provided they have a chip called eMarker, which is the case for most of them), but the investment is not profitable if it is only a matter of identifying a handful of cords. Benson Leung is working on a program that allows operating systems to warn the user when a “bad” cable is being used.
In the meantime, the solution is to identify the limitations of the cables in common use – a screen that does not light up, slow transfer, etc. – and to find out what the limitations are. The USB Implementers Forum also maintains a list of certified USB-C cables and other USB-C products on its website (not all cables are tested by this organization).
Then, before you buy a cable, check its technical data sheet. If you’re sure that this cable will always remain connected to a charger to power terminals, you can settle for a USB 2.0 cable.
But you still have to check whether it’s a 60 W cable (enough for most devices) or a 100 W cable (useful for MacBook Pro 15). The Apple charging cable (25 €) is suitable for this purpose. Cheaper from third party manufacturers such as AmazonBasics (€10).
If you’re looking for a more versatile cable, which can be used to connect an external SSD as well as a monitor, the Belkin USB-C 3.1 (10 Gbit/s) cable at €30 is appropriate, but be aware that it is limited to 60 W.
Otherwise, Moshi sells a cable with the same advantages (40 €) with the addition of power up to 100 W. The Anker Powerline II also ticks all the boxes (USB 3.1 to 10 Gbit/s, DisplayPort, 100 W) for a lower price, as it is currently €16. It is certainly the best choice, provided that its length, 90 cm, is enough for you.