Understanding USB Speeds

The Universal Serial Bus (USB) has become the standard method by which people connect their external device(s) to their computers or to other electronic devices. The biggest issue people have with USB (other than finding the right cord) is knowing the difference between the types of USB speeds.

When it comes to USB speeds the first thing to know is that currently there are four primary speeds. These are generally known as USB 1.x, 2, 3, and 4. Each version then has its own subsequent iteration number, which is often dropped in favor of the appropriate version number. For instance, the USB 2.1 version is still generally categorized and referred to as USB 2, with the iteration differentiator being dropped.

USB Speeds

USB 1.x – Released in 1996, USB 1.x was designed for transfer rates between 1.5 Megabits per second and 12 Megabits per second. USB 1.x had significant restrictions on what it could do, especially when compared to newer USB speeds. No real products were released with USB 1.x connectors. Rather, the industry waited until 1998 when USB 1.1 was released.

USB 2.0 – Released in 2000, USB 2.0 brought major improvements to the USB standard. USB 2.0 transfer rates went from the 1.x high end of 12 Megabits per second to the much faster 480 Megabits or 60 Megabytes. (Note that 480 Megabits is the same as 60 Megabytes.) Due in part to its faster speeds, USB 2.0 brought major adoption to the computer market, ushering in the end of other types of computer connectors.

USB 3.x – Released in 2008, USB 3.x saw yet again an increase in speeds. USB 3.0 speeds were vastly improved going from a max transfer rate of 60 Megabytes to 5 Gigabits. This speed improvement was essentially 10 times that of USB 2.0. USB 3.0 ports are specially labeled with either a blue plastic insert or a lightning icon. Since the 3.x specification came out there have been a couple of updates. In 2013 USB 3.1 saw another speed improvement from 5 Gigabits to 10 Gigabits. Then, in 2017, USB 3.2 was released allowing for a top speed of 20 Gigabits. The newer top speed was made utilizing the newer USB-C connector that has become very prevalent.

USB 4 – Released in 2019, USB 4 increases speeds yet again, with a top speed of 40 Gigabits per second. To say this increase, from USB 1.x to USB 4.0, is a big deal is an understatement. At a 2666570% increase from 1.x, there is a lot of data moving at any giving time.

An important thing to remember with regards to USB is its backward compatibility. This backward compatibility has long been a major benefit of USB, but it can cause a bit of a headache as well. What the backward compatibility means is that you can plug a USB 2.0 device into a USB 3.0 port, and it will still work. The caveat or headache, however, is that the USB 2.0 device will still only work at its designed speed, transferring data at USB 2.0 rates. Keep in mind that this can be tricky when using a USB 2.0 cable to connect your USB 3.0 device to your USB 3.0 port on your computer. So, you might think that your device and computer should both be transferring data at USB 3.0 speeds, except your cable may be slowing you down as it is still only designed for USB 2.0 speeds.

 This tip (13785) applies to Windows 7, 8, and 10.