What is USB (Universal Serial Bus) 3.0? (Explained)

What is USB (Universal Serial Bus) 3.0?

The USB 3.0 ports refer to the third generation Universal Serial Bus interfaces launched in 2008. These ports are also known as SuperSpeed USB.

Technically speaking, this particular standard of interface can be easily identified due to its blue color and is designed to offer much better performance than the previous versions by delivering greater data transfer speed and power efficiency.


  • The USB 3.0 ports can be easily identified due to the blue tongue in contrast to black or white of the USB 2.0 and the SuperSpeed variants can be identified by their unique logo.
  • The USB Type A is interchangeable while Type B is not and the USB 3.0 plugs fit in USB 2.0 Type A sockets but the USB 3.0 Type B plugs are bigger than USB Type B 2.0 counterparts.
  • The architecture also allows much better power management because the lower amount of multicast packets and unicast along with the asynchronous notifications allows the inactive links to go into reduced power state till they start passing packets actively.
  • As for the cables, though there is no maximum length specified for this particular USB standard, practically it should be about 10 feet or 3 meters. However, the cables should meet the minimum electrical specification of AWG 26 wires and copper cabling.

Understanding USB (Universal Serial Bus) 3.0

Understanding USB (Universal Serial Bus) 3.0

Technically, the USB 3.0 ports can transfer data at 5 GB/s which is much higher than 480 MB/s of USB 2.0.

This is without considering the fact that it is full duplex and the latter is half duplex. This offers 20 times higher potential total bidirectional bandwidth in comparison to USB 2.0.

However, in reality, the port cannot always achieve this speed. For example, the USB 3.0 storage drives may offer up to 50% improvement in performance and speed as compared to the USB 2.0 counterpart.

In terms of design, these ports do not poll devices continuously and therefore the load on the CPU or Central Processing Unit is significantly reduced.

These ports as well as USB 3.1 were renamed a number of times creating a naming jumble. You can identify USB 3.0 and USB 3.1 in the following ways respectively:

  • USB 3.0, USB 3.1 Gen 1, 3.2 Gen 1×1 and
  • USB 3.1, 3.1 Gen 2, 3.2 Gen 2×1.

The specifications of this port are quite similar to USB 2.0 but all these are much improved.

It offers much more alternative implementations but has the endpoints and the four transfer concepts such as control, bulk, isochronous and interrupt are retained.

With the electrical interface and the protocol being different, the specs of these ports define a physically separate conduit to transmit USB 3.0 traffic.

The particular changes made in the specs of this interface offer better performance and improvements in several areas such as:

  • Higher transfer speed of up to 5 GB/s in SuperSpeed or SS USB
  • Increased bandwidth with dual unidirectional data paths rather than one to receive and transmit data separately
  • Better power management with the U0 to U3 link power management states well defined
  • Enhanced bus use with the new feature and NRDY and ERDY packets used to asynchronously notify when the host is ready and
  • Better support for rotating media with an updated bulk protocol with the new Stream Protocol feature to handle a higher number of logical streams in an endpoint.
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The dual bus architecture of USB 3.0 and the tiered star structural topology with hubs at lower levels and a root hub provides backward compatibility and bus connectivity to the devices.

Since it is backward compatible, USB 3.0 Type A receptacle will support USB 2.0 Type A plug and a USB 3.0 Type A plug will support USB 2.0 Type A receptacle. These ports are used both on the host and the device side.

It is also the same for the USB 3.0 Type B standard receptacle and USB 2.0 Type B plug but a USB 3.0 B plug will not fit into a USB 2.0 Type B receptacle due to its larger side. This standard is however implemented at the device side.

The Micro-B plugs and receptacles are compatible with the Micro USB 2.0 plugs and are used in small portable devices such as digital cameras, smartphones and GPS devices.

However, this port will operate at the speed of the lower technology when you connect the new standard with it if you do not use an adapter.

As for power and charging, the standard offers 5 volts and 150mA for a unit load and 4.5 watts or 900mA for six unit loads.

However, it can use different specs for additional power such as the USB Battery Charging Specification that can offer up to 1.5 amperes or 7.5 watts for USB 3.0 and up to 100 watts for USB 3.1.

There are five more pins in the USB 3.0 as compared to its predecessor where the D−, D+, VBUS and GND pins are dedicated for USB 2.0 communications. The additional pins are:

  • One ground or GND_DRAIN pin for controlling EMI, maintaining signal integrity and draining wire termination and
  • Two differential pairs for SS data transfer and for full duplex signaling.

There are different types of connectors used such as:

  • USB Type A or USB 3.0 Standard A that are rectangular in shape and compatible with USB 2.0 and USB 1.1
  • USB Type B or USB 3.0 Standard B or USB 3.0 Powered B that are square in shape with a large notch at the top and are not compatible with older Type B receptacles but their receptacles are compatible with the plugs of the older standards
  • USB Micro A that are rectangular in shape and have two parts and are compatible only with USB 3.0 Micro AB receptacles and older USB 2.0 Micro A plug and
  • USB Micro B that are compatible with USB 3.0 Micro B and Micro AB receptacles only and older USB 2.0 Micro B plugs are compatible with the USB 3.0 Micro B and Micro AB receptacles.

There are usually no Mini A and Mini B plugs or receptacles in USB 3.0 as they are in the 2.0 version.

Working Principle

What is USB (Universal Serial Bus) 3.0

Data transfer via this port happens in perfect synchronization and is initiated when a request is made by the host and a response corresponding to it by the connected device.

These responses can be varied and have different effects such as:

  • A positive response results in a data transfer
  • A stall handshake response in the case of a halted endpoint
  • A NRDY or Not Ready response if there is not adequate data or buffer space when the request will not be processed and
  • An ERDY or Endpoint Ready response if the device is ready to allow rescheduling the transaction.
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Data is transmitted in an 8-bit or 1-byte stream and is usually jumbled.

This is done by the free running Linear Feedback Shift Register or LFSR which is reset after receiving or sending a COM symbol.

The scrambled data is then changed into 10-bit symbols with 8b/10b encoding.

This means that the receiver will be able to decode the data precisely even if there is any Electromagnetic Interference or EMI.

Uses of USB 3.0

This specific USB standard is ideal to use in more advanced and smaller devices that need higher bandwidth levels to function.

Depending on the types of it, some of the devices that use USB 3.0 ports are:

Is USB 3.0 and USB C Same?

No they are not. The most significant difference between a USB 3.0 and USB C is that the latter refers to a particular kind of USB connector but the former in general refers to the speed standard for the USB cables.

Typically, USB C is a kind of a thin, elongated, and oval shaped physical connection available on modern devices.

This connector replaces the USB A and Micro USB ports of the older devices.

Released in 2014, this connector is commonly used in devices including and not limited to:

  • Android smartphones
  • PlayStation 5 controllers
  • Headphones
  • Xbox Series X|S
  • Nintendo Switch and other smaller mobile devices.

The biggest advantages offered by this port are:

  • Convenience
  • Reversibility
  • Video output and
  • Charging with USB Power Delivery.

On the other hand, USB 3.0 is a standard which indicates how fast data is transferred over the cable as compared to the older versions.

Not all USB 3 cables use USB C connector and not all USB C cables support USB 3.

How to Know Whether a System has USB 3.0 Port?

There are two different ways to check whether a computer system is equipped with a USB 3.0 port such as by physical inspection and by using the Device Manager.

You can check the port physically and identify it if it has a blue tongue in it. Usually, most of these ports have it.

And, if it is an SS USB 3.0, it can be easily identified with the SuperSpeed logo above the port location.

You can also check it more accurately by using the Device Manager as follows:

  • Right-click on Windows icon
  • Select Device Manager
  • Select Universal Serial Bus controllers in the Device Manager window and
  • Find the USB port by the type.

However, on Apple, these ports are usually not marked or blue in color. You will need to check it from the System Information menu in the following way:

  • Click on Apple icon
  • Select About This Mac
  • Click System Report on the About This Mac window and click on More Info if you are using OS X 10.9 or lower
  • Click Hardware
  • Select USB and
  • Locate it by type.

In both cases, if there are no 3.0 or 3.1 ports, your computer is not equipped with USB 3.

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How to Enable USB 3.0 Ports?

You can set the USB 3.0 mode in your computer system easily by using the System Utilities screen and then following the necessary steps.

All you have to do from there is:

  • Select System Configuration
  • Go to BIOS or Platform Configuration
  • Click on System Options
  • Find and click on USB Options
  • Select USB 3.0 Mode
  • Press Enter
  • Select a setting
  • Press Enter and finally
  • Press F10 to save and exit.

However, before you do that, you should check a few other things to ensure that the port runs at Super Speed when enabled. These are:

  • Making sure that the hardware of the system is USB 3.0 capable
  • Checking the device information USB View to see bus speed in Device Manager and
  • Troubleshooting if the speed is not optimal.

If you find that the port is not operating properly, the first thing you should do is check the internal cables to see whether or not these are connected to the proper port.

If it is okay, you will need to install the latest and proper drivers to upgrade the USB 3.0. The steps to follow here are:

  • Clicking Windows Key
  • Locating and clicking on Device Manager in Control Panel
  • Looking for Universal Serial Bus Controllers in that window
  • Clicking on the small arrow beside the text to expand it
  • Looking for USB 3.0 or 3.1 driver name
  • Searching in Google for it
  • Visiting the site and
  • Clicking on the download link.

If there is no link, the first four steps to follow are the same as mentioned above. The additional steps to follow are:

  • Right clicking on USB 3.1 driver
  • Clicking on Properties
  • Clicking on Driver tab
  • Clicking on Update Driver and
  • Clicking on Search Automatically to locate the driver software updated.

Finally, you may also have to update the BIOS or Basic Input Output System and enable it.

Do all Computers have USB 3.0 Port?

Usually, most computers today come with both USB 2.0 and 3.0 ports.

However, there will be only two USB 3.0 ports usually because these ports are expensive and these ports are usually not much in demand.

This is because most of the peripherals like keyboards, mice, printers and others available today are not that demanding and work well using a USB 2.0.

Are USB 3.0 Ports Always Blue?

Usually, in most computers the USB 3.0 ports are blue in color.

However, it may not be in the newer PCs and the Mac computers never use blue ports.

Moreover, the USB 3.1 ports may have Teal Blue color which may look pretty green and since there is no official or universal color specification, it may even have a different greener shade.


The USB 3 standard has been around for more than a decade and is getting bigger and complicated to offer more functionality.

With the knowledge gained from this article it will take less time for you to adapt to this technology and know the major improvements that it offers in comparison to its predecessor USB 2.

About Dominic Cooper

Dominic CooperDominic Cooper, a TTU graduate is a computer hardware expert. His only passion is to find out the nitty gritty of all computers since childhood. He has over 12 years of experience in writing, computer testing, and research. He is not very fond of social media. Follow Him at Linkedin