USB and Thunderbolt are now intertwined, but that doesn’t always make things easier. Thunderbolt 4 and Thunderbolt 5 are backwards-compatible with other specifications, like USB4, Thunderbolt 3, and even older USB versions. This leads to the common misconception that USB4 is the same as Thunderbolt. In reality, USB4 only has the potential to match Thunderbolt 5 in a few areas — but only Thunderbolt actually realizes that potential.
It all comes down to the difference in minimum specifications between USB and Thunderbolt. Only a few minimum specifications are required for a cable or device to be branded as USB4, which means you might get vastly different performance from devices or cables that look identical. Thunderbolt, on the other hand, is all about consistency. When you see the Thunderbolt 5 logo, you know exactly what you’re going to get, and that’s what makes it great.
Faster speeds are just the beginning
Thunderbolt 5 is twice as fast as USB4, but that’s only the start
USB Type-C cables, whether they feature USB or Thunderbolt connectivity protocols, are used for much more than data transfer in 2026. Speed is just one factor in the equation, but Thunderbolt 5 has the edge. The Thunderbolt 5 standard mandates all cables and devices support a data transfer rate of 80Gbps. This fast, bidirectional transfer speed is four times the minimum speed offered by USB4. Taking things one step further, Thunderbolt 5 provides a “Bandwidth Boost” feature that bumps speeds up to 120Gbps for select graphics-intensive workflows.
Speed isn’t the main reason to opt for Thunderbolt 5 over USB4. That’s because USB4 is available at 80Gbps speeds. However, these speeds are only to be had with USB4 Version 2.0 cables, which are currently quite rare and visually indistinguishable from other USB4 cables. The majority of USB4 cables and devices offer 40Gbps speeds, or half that of Thunderbolt 5. That said, only 20Gbps speeds are required for a cable to sport USB4 branding.
It’s one of the main reasons Thunderbolt is more advantageous than USB. When you pick up a USB4 cable, it could support either 20Gbps, 40Gbps, or 80Gbps speeds. There’s a big swing between the minimum and maximum specifications of USB4. Without the right branding, you might never know which speeds or features a cable or device might support. Thunderbolt 4 is always 40Gbps and Thunderbolt 5 is always 80Gbps, simplifying matters.
Not all USB-C cables are the same
I only buy Thunderbolt 4 cables now, because USB-C cables aren’t made equal. These are the key differences to watch out for.
Thunderbolt 5 offers better display and charging specs
You get multiple 8K video outputs and at least 140W power delivery
Beyond speed, many USB4 features are optional. Generally, USB4 devices and cables are expected to support USB Power Delivery for charging and DisplayPort Alt mode for display output. The tricky part is that the minimum port power for USB4 is 7.5W, so fast charging isn’t a given. The number of supported displays, refresh rate, and resolution also vary wildly between USB4 ports and cables. It’s up to manufacturers to optionally expand on USB4’s minimum specifications, and even if they do, these changes aren’t visible from the outside.
Thunderbolt 5 guarantees minimum charging and display specs way beyond what USB4 offers. While the USB4 port power minimum is 7.5W, the Thunderbolt 5 specification requires a 140W minimum. The maximum is a whopping 240W, which is the same as USB4. This is another case where Thunderbolt 5 and USB4 have identical maximum speeds, but Thunderbolt 5 has the higher floor.
Display support is another major win for Thunderbolt, as one Thunderbolt 5 port or cable can power three 8K screens at 60Hz refresh rates. A single 4K display can reach refresh rates up to 540Hz, or dual 8K displays can be powered at 60Hz. In other words, whether you need multiple displays, a high-refresh-rate display, or a high-resolution display, Thunderbolt 5 has you covered. Meanwhile, USB4 maxes out at 8K/60Hz or 4K/240Hz — and even those are far from guaranteed.
Thunderbolt 5 also bakes in DisplayPort 2.1 support, while only USB4 Version 2.0 offers the same compatibility.
Cable standards are a mess, but you shouldn’t blame USB-C
Universal connectors are convenient in theory. Without visual differences, it’s hard to tell which USB-C cables support each connectivity standard.
The minimum specs are the separator
USB4 can match Thunderbolt 5 in some scenarios, but it’s not guaranteed
I’ve written the words “minimum specifications” more than a few times, but the emphasis is for good reason. With the absolute best specifications, USB4 Version 2.0 can match Thunderbolt 5 in data transfer speeds and charging speeds. The concern is that the worst USB4 cable is slower than Thunderbolt 5 by a wide margin. All the optional spec bumps and features within the USB4 standard create a convoluted experience where not every port or feature works the same.
There’s no such thing as a “worst Thunderbolt 5 cable,” because every Thunderbolt 5 port or cable supports the exact same specs. Nothing is optional. When you pick up a Thunderbolt 5 cable, you know it supports 80Gbps data transfer speeds, 140W charging, and multi-display support with DisplayPort 2.1. The base USB4 cable would only offer 20Gbps data speeds, 7.5W charging speeds, and a single supported display without the optional add-ons.
Instead of gambling on whether a USB4 port or cable is fully featured, choosing a Thunderbolt 5 device ensures you get the exact same features and specs — every single time.
