USB 3.0 - The Next Generation Interconnect
USB 3.0 |
Have you spent too much time waiting for large files to crawl between a computer and an external hard drive? Don't fret -- USB 3.0 has arrived. Not only can it move data faster and provide more power, but it's compatible with USB 2.0 devices.
Developed by the USB Implementers Forum (USB-IF), USB 3.0's SuperSpeed specification promises a theoretical top speed of 5Gbit/sec. versus USB 2.0's 480Mbit/sec.
The key to blending old and new is NEC's μPD720200 controller chip. It has the circuitry for USB 2.0 and 3.0 transfers inside and can use either, depending on what's plugged in. Right now, it's the only game in town, but look for other companies, including Symwave, Fujitsu and Via, to introduce their own USB 3.0 chips in the coming months.
The first round of USB 3.0 cards and devices works with Windows Vista and Windows 7; Apple hasn't decided whether to support the new standard. The basic software for USB 3.0 has been in the Linux kernel since last fall, and the needed drivers are slowly coming out.
There are already a few USB 3.0 devices available. To test them, I used a Lenovo ThinkPad W510USB 3.0USB 3.0 with USB 3.0 built in. I tried out a variety of new devices, including the Buffalo DriveStation USB 3.0 HD-HXU3 external hard drive; a StarTech SuperSpeed USB 3.0 to SATA Hard Drive Docking Station in combination with my current Western Digital WD Caviar Blue external drive; and a Seagate BlackArmor PS 110 USB 3.0 Performance Kit, a portable hard drive that includes its software on a USB 3.0 ExpressCard.
What's new in USB 3.0?
Unlike the change from USB 1.0 to USB 2.0, USB 3.0 brings actual physical differences to the connectors. The flat USB Type A plug (that goes into the computer) looks the same, but inside is an extra set of connectors; the edge of the plug is colored blue to indicate that it's USB 3.0.
On the other end of the cable, the Type B plug (that goes into the USB device) actually looks different -- it has an extra set of connectors, so it looks a bit like a USB plug that's been crimped a little ways down one end. There's also a new Micro Type B plug that has all its connectors laid
out horizontally.
out horizontally.
USB 3.0 - Types and architecture |
USB 3.0 - Plug Architecture |
The reason for the new connector is that the USB 3.0 cable contains nine wires (four more than a USB 2.0 cable); eight carry data and one is used as a ground. Despite the increase in wires, however, the cables should be no thicker than those used by USB 2.0. There will be a big difference in performance, however. USB 2.0 is like a single-lane country road that needs to handle the morning-commute traffic in and out of L.A. There are jams and slowdowns when too much data is going back and forth. With nine wires available, USB 3.0 has an additional two lanes of traffic in each direction to smooth the flow between the computer and the device.
Unlike USB 2.0, which requires synchronous transfers, where the data is asked for and then sent, the 3.0 host controller doesn't have to poll the USB device every time it wants to send data. This streamlines the flow with high-speed asynchronous transfers.
While SuperSpeed's peak speed is 5Gbit/sec., it will drop to a slower speed on occasion -- for example, when it moves data into and out of older devices or when it's being used with a too-long cable.
On top of faster data speeds, USB 3.0 provides up to 150 milliamps (mA) of electricity -- 50% more than USB 2.0 -- to an unconfigured device while the computer it's connected to is finding and loading its needed software. Once the device has been configured and accepted by the computer's operating system, USB 3.0 can deliver 900mA to the device, compared with USB 2.0's 500mA. This should be more than enough to power a hard drive or a camcorder -- or even a USB device (such as a monitor or a projector) that needs more power than is available via a USB 2.0 port.
USB 3.0 offers power conservation as well. While USB 2.0 is either on or off and wastes power when it isn't being used, the new spec comes with three levels of power use that draw progressively less power.
But be aware that first-generation USB 3.0 implementations are power-hungry. The Lenovo ThinkPad W510 that I used for testing ran for 2 hours 19 minutes while continuously playing music from a USB 3.0 external drive -- and ran for an additional 34 minutes when it used a USB 2.0 port.
Conclusions
USB 2.0, introduced in 2002, is obviously showing its age. "Eight years is a long time to wait for an update," says Brian O'Rourke, principal analyst at In-Stat, a market intelligence company.
"We've clearly outgrown USB 2.0, and the new spec is aimed at those who move large chunks of data. Moving big files around will no longer seem to take forever," he adds.
There will, no doubt, be an onslaught of USB 3.0 equipment in the near future, including computers, drives, webcams and memory keys. According to O'Rourke, "2011 will be the year of USB 3.0, with a huge variety of devices available. By 2013, I expect that over 1 billion USB 3.0 drives will be sold worldwide."
In my tests, the first round of USB 3.0 hard drives delivered 400Mbit to 440Mbit/sec. of actual throughput. This is between two and three times what USB 2.0 is capable of and can reduce the time to transfer 10GB of data from about 10 minutes to between 3 and 4 minutes.
In the coming years, look for this increased speed to enable new technologies, such as kiosks that can put an entire high-definition movie on a memory key in a minute, self-powered DisplayLink USB high-resolution monitors and flash-based HD camcorders that can transfer their raw video in a few minutes.
For me, the most exciting step forward is that USB 3.0's speed will make it possible to put an entire system -- OS, programs and data -- on a memory key that's fast enough to work seamlessly. Who needs to lug a laptop around when you could just carry a memory key and a USB 3.0 card, and plug them into any computer?
Meanwhile, if you're shopping around for a new system, it's a good idea to see whether the computer offers USB 3.0. If it doesn't, then make sure it at least has an ExpressCard slot, so that when it's time to start buying USB 3.0 devices, you can also get an adapter -- and take advantage of the speed.
USB 3.0 Performance
DiskMark | Sequential Read/Write | Random Read/Write | Read from/ write to folder | |
Buffalo DriveStation w/Seagate ExpressCard | 317 | 334.4Mbps/ 340.0Mbps | 26.9Mbps | 382.8Mbps/ 399.5Mbps |
Buffalo DriveStation w/StarTech 2 Port ExpressCard | 316.3 | 351.2Mbps/ 440.0Mbps | 27.4Mbps | 228.6Mbps/ 211.7Mbps |
Buffalo DriveStation w/ThinkPad W510 | 319.9 | 334.4Mbps/ 354.4Mbps | 26.2Mbps | 439.2Mbps/ 408.5Mbps |
Buffalo DriveStation w/USB 2.0** | 115.2 | 132Mbps/ 98.4Mbps | 25.4Mbps | 172.4Mbps/ 176.2Mbps |
Seagate BlackArmor w/Seagate ExpressCard | 345.3 | 340.8Mbps/ 399.2Mbps | 23.3Mbps | 204.8Mbps/ 168.7Mbps |
Seagate BlackArmor w/StarTech 2 Port ExpressCard | 432.9 | 466Mbps/ 468.0Mbps | 23.6Mbps | 285.4Mbps/ 226.9Mbps |
Seagate BlackArmor w/ThinkPad W510 | 275.4 | 296.8Mbps/ 276.8Mbps | 22.6Mbps | 372.7Mbps/ 226.7Mbps |
Seagate BlackArmor w/USB 2.0** | 148.2 | 164Mbps/ 140.8Mbps | 22.7Mbps | 137.6Mbps/ 117.4Mbps |
StarTech Docking Station* w/Seagate ExpressCard | 386.1 | 391.2Mbps/ 438.4Mbps | 24.3Mbps | 413.6Mbps/ 349.2Mbps |
StarTech Docking Station* w/StarTech 2 Port ExpressCard | 385.9 | 392.0Mbs/ 437.6Mbps | 24.0Mbps | 325.8Mbps/ 189.2Mbps |
StarTech Docking Station* w/ThinkPad W510 | 314.8 | 374.4Mbps/ 300Mbps | 22.1Mbps | 414.6Mbps/ 235.3Mbps |
StarTech Docking Station* w/USB 2.0** | 142.1 | 164.8Mbps/ 139.2Mbps | 23.2Mbps | 117.4Mbps/ 131.4Mbps |
*With WD Caviar Blue drive
**Using Fujitsu LifeBook A6220
**Using Fujitsu LifeBook A6220
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