If your drawer is overflowing with identical-looking USB-C cables, you are not alone. The connector has become universal, but the capabilities hiding inside each cable vary wildly. The USB Implementers Forum (USB-IF), the body that governs the standard, is explicit in its Type-C language guidelines: USB Type-C is not USB 3.2, it is not USB4, and it is not USB Power Delivery. Those are separate technologies that may or may not travel through the same reversible plug. A manufacturer can ship a USB-C port that supports none of them.
- Connector ≠ capability: USB-C describes the physical shape only, not data speed, charging power or video support.
- Logos matter: Certified cables must carry their speed and wattage on the connector or packaging.
- Thunderbolt guarantees minimums: Intel’s certification enforces features that plain USB-C leaves optional.
Why two identical cables perform so differently
The answer is internal wiring. A USB 2.0 Type-C cable lacks the high-speed contacts needed for faster signaling. According to the USB-IF, it physically cannot carry USB 3.2 or USB4 traffic and tops out at 480 Mbps. Plug a fast external SSD into a fast laptop with that cable and the whole chain drops to USB 2.0 speeds.
The most familiar example sits in many pockets. Apple’s specification page for the iPhone 17 states that its USB-C connector supports charging, DisplayPort and USB 2 at up to 480 Mb/s. It is the same physical port as a USB4 laptop, but the data rate is a generation behind.
The USB-IF has also asked manufacturers to stop advertising specification names such as USB 3.2, USB4 version 1.0 or 2.0, and SuperSpeed on packaging. Instead, its data performance guidelines define five commercial labels: USB 80Gbps, USB 40Gbps, USB 20Gbps, USB 10Gbps and USB 5Gbps. Below those sits USB 2.0 at 480 Mbps. The official USB4 page adds that the architecture builds on the Thunderbolt protocol contributed by Intel, and that 80 Gbps is only reachable with cables certified for that rate. Everything remains backward compatible, so a link negotiates down to the slowest component in the chain.
Charging, wattage and Europe’s mandate
USB Power Delivery (USB PD) is the protocol through which a charger and a device negotiate how much energy flows. The USB-IF’s USB PD page notes that revision 3.1, announced in 2021, raised the ceiling to 240 W. The previous limit was 100 W at 20 V with 5 A cables. New fixed voltages of 28, 36 and 48 V enable 140, 180 and 240 W respectively.
Once again, the cable is decisive. The USB-IF requires every USB-C to USB-C cable that passes certification to carry a printed or embossed logo showing its speed and power rating. Its own example: a 20 Gbps cable rated for 20 V and 3 A must be marked 20Gbps/60W. USB 2.0 cables carry only a 60 W or 240 W logo, because their 480 Mbps data rate is not part of the seal.
In Europe, law reinforces the standard. Directive (EU) 2022/2380 obliges a USB-C receptacle on mobile phones, tablets, digital cameras, headphones, handheld consoles, portable speakers, e-readers, keyboards, mice, portable navigation systems and earbuds from 28 December 2024, and on laptops from 28 April 2026. Any device on that list charging by cable above 5 V, 3 A or 15 W must incorporate USB PD; other fast protocols may coexist but cannot replace it. Packaging must also show a pictogram indicating whether a charger is included and a label stating the minimum and maximum power the device needs, plus the text “USB PD” where supported.
Where Thunderbolt fits in
Thunderbolt uses the same USB-C connector but comes with guaranteed minimums. In its technical brief on Thunderbolt 5, Intel explains that the standard builds on USB4 version 2.0 and DisplayPort 2.1, delivers 80 Gbps in each direction, and uses a Bandwidth Boost mode that allocates 120 Gbps for transmission and 40 Gbps for reception when video demand is high. The same document sets a requirement to charge the host computer at up to 140 W, with an option to reach 240 W, and video support for two 6K displays, compared with two 4K displays on Thunderbolt 4.
The practical difference with USB4 is certification. Intel publishes a list of mandatory requirements for the Thunderbolt logo, while the USB-IF makes clear that a USB-C product is not obliged to support USB4 or Power Delivery. With Thunderbolt you know what you are buying; with a plain USB-C port, you have to read the spec sheet.
Choosing a cable without getting burned
- Phone charging only: check the device’s request. Apple states the iPhone 17 reaches fast charging with a 40 W or higher adapter, so a certified 60 W cable covers it; a 240 W cable is not wasted either, since charger and device negotiate the power.
- Laptop: read the maximum wattage on its label; above 60 W, choose a cable marked 240 W.
- External drive or SSD: look for the speed logo (10, 20 or 40 Gbps) and confirm the computer port matches. The slowest link sets the pace.
- Monitor: the port must support video (DisplayPort over USB-C or Thunderbolt) and the cable must be high-speed; per the USB-IF, a USB 2.0 Type-C cable lacks the lines used by video alternate mode.
- Unmarked cable: treat it as USB 2.0 until proven otherwise.
The USB-C story was never about the connector, which ranks among the best things to happen to consumer electronics, but about marketing that treated it as a synonym for “fast.” European law has fixed the plug and the charger, and the USB-IF has fixed the naming. What remains is for retailers to display those logos before checkout. Until then, the safest rule is to buy cables with speed and wattage printed on the connector itself.