Comparing USB 2.0 and USB 3.0 standards

Technological progress in relation to computers is especially pronounced. Almost every year new technologies, interfaces, systems, chips and other architectures are introduced. This also affects such familiar things as USB.

So, for example, starting from 2017-2018, the USB Type-C interface began to be actively introduced. It has a symmetrical, oval connector, and is generally not compatible with traditional rectangular Type-A.

But if Type-C differs dramatically from Type-A, then the differences between USB 2.0 and USB 3.0 are not so obvious. Let’s figure out what they are and whether it is worth overpaying for a computer or a flash drive with a new interface.

USB 2.0

USB 2.0 is a relatively old standard. The technology was introduced in early 2000 and at that time offered such a high data transfer rate that it received the «subtitle» High-Speed.

In particular, the maximum data transfer rate regulated by this protocol is 480 megabits (60 megabytes) per second. It is achieved on devices with Hi-Speed ​​support. These are various flash drives, cameras, cameras and so on.

However, the speed parameter is theoretical. In practice, the average data transfer rate is about 20 megabytes per second.

When developing the 2.0 standard, the creators sought to ensure maximum compatibility with legacy interfaces. So, it is still a four-pin connector (5-pin on devices with ground), which carries a current with a voltage of 5 Volts and a power of 0.5 Amperes on computers. However, the bus controller has been redesigned to increase the data transfer rate.

In general, at the moment, the 2.0 standard is still a universal interface, which will even be supported for at least a few years. The low price of controllers, a huge number of compatible devices and a well-developed interaction mechanism make it suitable for use in home and office environments.

More precisely, it is relatively slow. Generation 3.0 certainly outperforms it in terms of throughput, but the actual data transfer rate depends on the performance of the drive, the type of files, the file system, and a lot of third-party parameters.

USB 3.0

The USB 3.0 interface was introduced in 2008 and, interestingly, was not an improvement on the previous generation, but a complete redesign of it. Changes have even affected the design of the connector!

So, Superspeed revisions use nine contacts: 2 main signal, 2 main current, 2 additional signal, 2 additional current and — optionally — «ground». However, the main ones are located in the same places as the 2.0 standard, due to which compatibility with previous generations is achieved.

They also increased the current supplied to the connector — now it is 0.9 Amperes. As a result, three goals were achieved:

1. You can connect more devices to one connector on the motherboard using the «tree» method (that is, to the «motherboard» — a keyboard with an external USB connector, to the keyboard — a card reader, and to it — a flash drive, for example);

2. Some devices no longer require external power to operate, they take all the necessary current from the interface;

3. Mobile devices connected to the computer charge faster.

But the main advantage of the revision is the increased data transfer rate. For the 3.0 standard, it is up to 5 gigabits (0.6 gigabytes) per second. Of course, this is a theoretical indicator, in practice it is limited by the capabilities of the receiving device.

The 3.0 generation interface paved the way for new possibilities for connected devices. So, in its subsequent revisions you can find:

1. Compatible with DisplayPort for connecting screens;

2. Thunderbolt support for the highest possible data transfer rate (this is necessary, for example, for external video cards to work);

3. Support for two-way current transfer (that is, a master device is selected that charges the slave device — for example, you can charge a laptop from a smartphone).

This development is not limited. In the future, other ways to use the connectors with maximum benefit will be found.

The high cost of the USB 3.0 standard is especially pronounced in the pricing of flash drives and similar external media. So, a device equipped with 2.0, with a capacity of 8 GB, can now be bought for 3-5 dollars. But for a flash drive of the same volume, but already with 3.0, you will have to pay 10-15 dollars.

Versions 3.1 and 3.2

Further development of the interface led to the fact that the developers were faced with hardware limitations. It was not possible to equip the connector with a bunch of connectors and at the same time ensure compatibility with outdated iterations. Then it was decided to rework it.

This is how Type-C was born. This type of interface is equipped with 24 pins, thanks to which many additional features have been achieved. Firstly, it is symmetrical, so you no longer need to twist the flash drive before installation. Secondly, it fully supports Power Delivery and can transmit up to 20 volts of current. And finally, the maximum current in it is 5 Amps!

True, these additional features did not fit into the framework of 3.0. So there were two revisions — 3.1 and 3.2. They managed to use additional data transmission channels, thanks to which the maximum throughput was 10 gigabits (1.2 gigabytes) per second!

But it is worth noting that there are no devices that support such high speeds yet. Usually there is a limit on the speed of the drive or the clock frequency of the controller.

Comparison

So, USB 2.0 and USB 3.0 differ structurally and technologically. Now is the time to compare them and choose which is better!

USB 3.0 is used primarily for data transfer and power. It is necessary for the fast operation of connected flash drives, smartphones and other drives. Also, in some cases, external devices such as video cards, sound adapters, and so on are connected to it.

USB 2.0 is used in devices that do not require the highest speed. It can even now, in 2019, be found in the latest keyboards, mice, printers and scanners. Low price, good compatibility and sufficient bandwidth for most tasks will keep it relevant for a long time.