USB-C Explained: Why One Cable Doesn't Fit All
USB-C is everywhere, but not all USB-C cables are the same. Here's what you need to know to avoid buying the wrong one.
USB-C Explained: Why One Cable Doesn't Fit All
USB-C was supposed to simplify everything — one connector for charging, data, and video. And it does, sort of. The problem is that the USB-C connector is just the physical shape. What the cable actually supports varies wildly.
The Connector vs. The Protocol
Think of USB-C as the shape of the plug. The protocol is what travels through it:
- USB 2.0 — 480 Mbps. Fine for charging and basic peripherals. Most cheap cables are this.
- USB 3.2 Gen 1 — 5 Gbps. Good for external drives and faster peripherals.
- USB 3.2 Gen 2 — 10 Gbps. Great for SSDs and docks.
- USB4 / Thunderbolt 4 — 40 Gbps. The full experience: fast data, video output, and high-wattage charging through one cable.
Charging: Watts Matter
Not every USB-C cable supports fast charging:
- A basic cable might cap at 15W (5V/3A)
- A good cable supports 60W (20V/3A) — enough for most laptops
- Premium cables handle 100W (20V/5A) or even 240W with the EPR spec
If your laptop charger is 65W but your cable only supports 15W, you'll get a trickle charge at best.
How to Buy the Right Cable
- For phone charging — Any USB-C cable works, but get one rated for at least 60W if you want fast charging
- For external SSDs — You need USB 3.2 Gen 2 or better for full speed
- For monitors / docks — Look for Thunderbolt 4 or USB4 cables with video output support
- For just charging a keyboard or mouse — The cheapest USB 2.0 cable is perfectly fine
The Label Problem
Unfortunately, cables don't always clearly state their capabilities. Look for:
- The USB logo with the speed rating (SS for SuperSpeed, the number for Gbps)
- Thunderbolt lightning bolt symbol
- Wattage rating printed on the cable or packaging
When in doubt, buy from reputable brands that clearly list specs. A $5 cable that doesn't do what you need is more expensive than a $15 cable that does.