USB 3.0 Speed

There are currently three speed modes defined by the latest USB 3.0 specification. They are SuperSpeed, Hi-Speed and Full-Speed. The new SuperSpeed mode has a transfer rate of 4.8Gbps. While the specification retains Hi-Speed and Full-Speed USB mode, commonly known as USB 2.0 and 1.1 respectively, the slower modes still operate at 480Mbps and 12Mbps respectively and are kept to maintain backward compatibility. Check out this page for a comparison between USB 3.0 and other competing interfaces such as eSATA, FireWire and Thunderbolt.

How fast exactly are these USB 3.0 drives?
To illustrate how fast the USB 3.0 drives whether they be flash drives, 2.5" portable drives, 3.5" desktop drives, we plotted their RichCopy real-world benchmark data in bar graphs so you can easily tell the performance leader in each storage peripheral subcategory.

Flash Drives
For the ultra portable storage category, we tested LaCie FastKey, Kingston Data Traveler Ultimate, Kingston HyperX Max, Super Talent SuperCrypt, Super Talent Express RAM Cache, Super Talent Express. Corsair Flash Voyager GTR is just a fast USB 2.0 flash drive we picked for reference.

2.5" Portable Hard Drives
Here, we selected ioSafe Rugged Portable (7200 rpm), Iomega eGo USB 3.0 (5400 rpm), LaCie Rikiki USB 3.0 (5400 rpm), Seagate GoFlex Ultra Portable (5400 rpm), Seagate GoFlex Slim (7200 rpm), Western Digital My Passport Essential SE (5200 rpm).

3.5" Desktop Hard Drives
We tested a number of traditional self-powered desktop drives as well as enclosures including ioSafe SoloPRO (fireproof), LaCie 2Big RAID, Seagate GoFlex Desk, SIIG USB 3.0 Dock and Thermaltake BlacX 5G USB 3.0 Case.

How does USB 3.0 achieve the extra performance?
USB 3.0 achieves the much higher performance by way of a number of technical changes. Perhaps the most obvious change is an additional physical bus that is added in parallel with the existing USB 2.0 bus. This means that where USB 2.0 previously had 4 wires (power, ground, and a pair for differential data), USB 3.0 adds 4 more for two pairs of differential signals (receive and transmit) for a combined total of 8 connections in the connectors and cabling. These extra two pairs were necessary to support the SuperSpeed USB target bandwidth requirements, because the two wire differential signals of USB 2.0 were not enough.

Furthermore, the signaling method, while still host-directed, is now asynchronous instead of polling. USB 3.0 utilizes a bi-directional data interface rather than USB 2.0's half-duplex arrangement, where data can only flow in one direction at a time. Without getting into any more technical mumbo jumbo, this all combines to give a ten-fold increase in theoretical bandwidth, and a welcome improvement noticeable by anyone when SuperSpeed USB products hit the market.

Isn't USB 2.0 fast enough?
Well, yes and no. USB 2.0 for many applications provides sufficient bandwidth for a variety of devices and hubs to be connected to one host computer. However, with today's ever increasing demands placed on data transfers with high-definition video content, terrabyte storage devices, high megapixel count digital cameras, and HD video capture and portable media players, 480Mbps is not really fast anymore.

Furthermore, no USB 2.0 connection could ever come close to the 480Mbps theoretical maximum throughput, making data transfer at around 320Mbps (40MB/s) - the actual real-world maximum. Similarly, USB 3.0 connections will never achieve 4.8Gbps. We will likely see a real-world maximum rate of 400MB/s with overheads. At this speed, USB 3.0 is a 10x improvement over USB 2.0.