July 1, 2026, 8:12 am | Read time: 3 minutes

USB-C has long been established as the standard connection for smartphones, notebooks, tablets, and accessories. The problem: Although all cables have the same connector, they differ greatly in their technical properties. Some are only suitable for charging, while others transfer data–often at very different speeds. There are also significant differences in maximum charging power.

This regularly causes confusion in everyday life. Anyone who has ever connected an iPhone, an external SSD, or a monitor to a Mac and wondered about slow data transfer or a missing connection knows the problem. From the outside, it’s practically impossible to tell whether a cable merely meets the minimum requirements or supports modern standards like USB-4 or Thunderbolt.

“WhatCable” automatically analyzes connected cables

This is where the free Mac app “WhatCable” comes in, available for download on GitHub. After connecting a USB-C cable, the software analyzes its properties and clearly displays the most important information. Users can see at a glance whether the cable can transfer data, what maximum data rate is supported, and with what power connected devices can be charged.

Additionally, the app informs users about which USB or Thunderbolt standard the respective cable supports. Especially for those who use multiple USB-C cables or frequently switch accessories, this allows for quickly identifying the right cable for each purpose. This saves time and prevents troubleshooting with seemingly defective devices or slow data transfers.

There are worlds between USB 2.0 and Thunderbolt

The specifications show just how big the differences really are. A simple USB 2.0 cable only achieves a data rate of 480 Mbit/s and supports charging power up to 60 watts. In contrast, modern USB4 cables can handle up to 40 Gbit/s and can power devices with up to 100 watts.

Also interesting: What you need to know about USB ports and cables

Thunderbolt cables are even more powerful. They also offer transfer rates of up to 40 Gbit/s but allow charging power of up to 240 watts. Those who regularly copy large amounts of data, connect high-resolution monitors, or charge powerful notebooks will benefit from a high-quality cable. With “WhatCable,” you can check without technical knowledge whether the existing USB-C cable actually meets your needs.