USB Speed Comparison: From USB 1.0 to USB4

Last Updated: July 15, 2026

USB speed should be easy to compare, but the names often make it harder than it needs to be. The same 5 Gbps connection may be labeled USB 3.0, USB 3.1 Gen 1, or USB 3.2 Gen 1×1. Meanwhile, two cables with identical USB-C connectors can have completely different data speeds.

The clearest way to compare USB performance is to look at the stated data rate rather than relying only on the version name or connector type. This ByteCable guide matches the older USB names with their actual speeds, explains why rated and real-world speeds differ, and shows what to check when choosing a cable.

USB Speed Comparison Chart

These are maximum rated data speeds, not guaranteed file-transfer results. The actual speed also depends on the computer port, cable, connected device, and the hardware reading or writing the data.

USB4 Version 2.0 can also use an optional 120 Gbps/40 Gbps asymmetric mode for applications that need much more bandwidth in one direction, particularly advanced display connections. It is not the normal transfer speed of every USB4 cable or device.

USB 3.0 vs 3.1 vs 3.2: Why the Names Are Confusing

USB 3.x naming is confusing because older speeds were renamed when newer specifications were released. A new name did not always mean a new or faster connection.

The original USB 3.0 specification introduced a 5 Gbps data rate. When USB 3.1 arrived, that same 5 Gbps mode became USB 3.1 Gen 1. It was renamed again as USB 3.2 Gen 1×1. All three names describe the same maximum speed:

USB 3.0 = USB 3.1 Gen 1 = USB 3.2 Gen 1×1 = 5 Gbps

The 10 Gbps mode followed a similar path. It was introduced as USB 3.1 Gen 2 and later renamed USB 3.2 Gen 2×1:

USB 3.1 Gen 2 = USB 3.2 Gen 2×1 = 10 Gbps

USB 3.2 then added a two-lane mode capable of 20 Gbps, known as USB 3.2 Gen 2×2. This does not mean every product described as USB 3.2 supports 20 Gbps. The USB 3.2 specification includes 5 Gbps, 10 Gbps, and 20 Gbps modes.

To reduce this confusion, the USB Implementers Forum now recommends consumer-facing names based on performance: USB 5Gbps, USB 10Gbps, USB 20Gbps, USB 40Gbps, and USB 80Gbps. When comparing products, the numeric data rate is more useful than the specification revision printed beside it.

USB Versions and Speeds Explained

USB 1.0 and USB 1.1 Speeds: 1.5 Mbps and 12 Mbps

The first USB generation provided Low-Speed operation at 1.5 Mbps and Full-Speed operation at 12 Mbps. These speeds were intended for peripherals that exchanged small amounts of data rather than transferring large files.

USB 1.x is no longer relevant when choosing a high-speed cable, but its lower-speed modes remain part of USB’s backward-compatible design. That is why simple peripherals can continue to work when connected to newer USB systems.

USB 2.0 Speed: 480 Mbps

USB 2.0 increased the maximum data rate to 480 Mbps and became known as Hi-Speed USB. Although much faster standards are now available, USB 2.0 is still widely used where basic data communication is sufficient.

It is also common in USB charging cables. A cable may support high charging power while providing only USB 2.0 data speed, because charging power and data transfer are separate capabilities.
Dividing 480 Mbps by eight gives a theoretical maximum of 60 MB/s. Actual file transfers are lower because the connection uses part of its capacity to manage the transfer, and the connected device may have its own performance limit.

USB 3.0 Speed: 5 Gbps

USB 3.0 raised the maximum data rate to 5 Gbps, more than ten times the rated speed of USB 2.0. It was later renamed USB 3.1 Gen 1 and USB 3.2 Gen 1×1, but the speed remained unchanged.
Today, USB 5Gbps is the clearest way to describe this performance level. A product marked only as USB 3.0, USB 3.1 Gen 1, or USB 3.2 Gen 1 should still be understood as a 5 Gbps connection. ByteCable groups cables using these older names under its USB 3.0 cable category.

USB 3.1 Gen 2 Speed: 10 Gbps

USB 3.1 introduced a new 10 Gbps mode called USB 3.1 Gen 2. It was later renamed USB 3.2 Gen 2×1 and is now more clearly described as USB 10Gbps.

USB 3.1 Gen 2 Speed: 10 Gbps

USB 3.1 introduced a new 10 Gbps mode called USB 3.1 Gen 2. It was later renamed USB 3.2 Gen 2×1 and is now more clearly described as USB 10Gbps.

The `Gen 2` part matters. A product described simply as USB 3.1 may refer to either the 5 Gbps Gen 1 mode or the 10 Gbps Gen 2 mode. When choosing a USB 3.1 cable, confirm that the specification states USB 3.1 Gen 2 or 10 Gbps.

USB 3.2 Gen 2×2 Speed: 20 Gbps

USB 3.2 Gen 2×2 reaches 20 Gbps by using two 10 Gbps data lanes over USB-C. It is commonly described as USB 20Gbps.

The full name is important here because `USB 3.2` alone does not guarantee 20 Gbps. It may also refer to the earlier 5 Gbps or 10 Gbps modes that were absorbed into the USB 3.2 specification. A USB 3.2 cable intended for 20 Gbps operation should specifically state USB 3.2 Gen 2×2 or USB 20Gbps.

The host port and connected device must also support the 20 Gbps mode. If either end supports only 10 Gbps, a 20 Gbps cable cannot raise the connection above 10 Gbps.

USB4 Speed: 20 Gbps, 40 Gbps, and 80 Gbps

USB4 uses the USB-C connector and supports several performance levels rather than one fixed speed. The first USB4 specification included 20 Gbps and 40 Gbps modes. USB4 Version 2.0 later increased the maximum symmetric data rate to 80 Gbps.

This means `USB4` alone still does not tell you the exact speed. A USB4 port or cable should be accompanied by a specific rating such as USB 20Gbps, USB 40Gbps, or USB 80Gbps.

USB4 can carry data and display traffic over the same connection, making its available bandwidth particularly useful for docks, displays, and high-performance storage. However, connecting a USB 40Gbps cable does not make every device run at 40 Gbps. The complete connection must support that rate.

Theoretical vs Actual USB Transfer Speed

USB data rates are normally stated in megabits or gigabits per second, while file-transfer software usually reports megabytes per second. There are eight bits in one byte, so a 5 Gbps rating converts to a theoretical 625 MB/s.

That number is an arithmetic ceiling, not the speed you should expect to see during every transfer. USB uses some bandwidth to organize and manage the data. The storage device must also read or write fast enough to keep up with the connection.

The final result is determined by the slowest relevant part of the path. If a computer has a 10 Gbps port and an external drive supports 10 Gbps, but the cable supports only 5 Gbps, the connection is limited to 5 Gbps. Replacing that cable with a 20 Gbps model will not push the same system beyond 10 Gbps because the port and drive remain the limit.

File type also affects the result. Moving one large file is generally easier for a storage device than processing thousands of small files. For this reason, two transfers over the same USB connection may report different speeds without anything being wrong with the cable.

USB Charging Speed vs Data Transfer Speed

Charging power and data speed should be checked separately. A USB-C cable rated for 100W or 240W may carry data only at USB 2.0 speed. Another cable may support both high charging power and 20 Gbps or 40 Gbps data.

This distinction is easy to miss when a product is promoted mainly by its charging rating. For a complete comparison, look for both a wattage rating and a data rate. If only the wattage is provided, the cable’s data performance is still unknown.

Does USB-C Determine Data Transfer Speed?

USB-C describes the shape and design of the connector. It does not define one data speed.

A USB-C cable may support USB 2.0 at 480 Mbps, USB 5Gbps, USB 10Gbps, USB 20Gbps, or USB4 performance. Two cables can therefore have the same reversible connectors while being designed for very different jobs.

USB-A also covers more than one speed. Depending on the port and cable, a USB-A connection may support USB 2.0, 5 Gbps, or 10 Gbps. The 20 Gbps USB 3.2 Gen 2×2 mode and USB4 rely on USB-C, but the presence of USB-C still does not guarantee either one.

How to Choose the Right USB Speed

The best USB speed is the one that matches the connection you are building. Choosing the newest or highest number does not automatically improve performance.

USB 2.0 is sufficient when charging and basic communication are more important than moving large amounts of data. USB 5Gbps is a practical starting point for general file transfers and mainstream peripherals. USB 10Gbps provides more room for faster storage without requiring the less common 20 Gbps mode.

USB 20Gbps makes sense when the host and device both support USB 3.2 Gen 2×2. Without that support at both ends, it falls back to a lower speed. USB 40Gbps and USB 80Gbps are aimed at connections with much higher bandwidth requirements, including multi-function docks, high-resolution displays, and fast external storage.

Before choosing a cable, confirm three specifications:

1. The maximum data rate supported by the host port
2. The maximum data rate supported by the connected device
3. The data rate and charging power supported by the cable

The cable should meet the requirements of both ends. Extra performance may provide room for future equipment, but it cannot increase the capability of the devices already connected.

Conclusion

USB version names have changed repeatedly, especially across USB 3.0, USB 3.1, and USB 3.2. The easiest way to compare them is to look for the actual data rating: 480 Mbps, 5 Gbps, 10 Gbps, 20 Gbps, 40 Gbps, or 80 Gbps.

That rating describes the maximum capacity of the connection, not a guaranteed file-transfer result. The host, cable, and connected device must all support the required speed, and the connection runs according to its slowest component. Connector type and charging wattage should be checked separately rather than used as shortcuts for determining data performance.