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After this years CES, it's clear that USB 3.0 is here to stay. Wtih a tidal wave of consumer devices looming on the horizon, we've decided to help clear up confusion about USB 2.0's successor. Here's all the information you need to know about USB 3.0, organized into a brief FAQ.
USB 3.0 features a number of features not seen in USB 2.0. The most important of these is the "SuperSpeed" bus--two additional pairs of wire which allow for significantly faster transfers than before, with full duplex transfers. These additional connections require a different, larger form factor for USB 3.0 plugs. USB 3.0 also improves on the power-management capabilities of USB 2.0, offering advanced efficiency features, as well as the ability to provide more power to USB 3.0 devices. About the only drawback to USB 3.0 is that the maximum cable length for high speed transmission is likely to drop to around 10 feet, from 15 feet with USB 2.0.
Yes it is. A USB 2.0 device will be able to plug into a USB 3.0 port and will work just fine. Also, a standard A USB 3.0 plug can be inserted into a USB 2.0 A port, operating at USB 2.0 speeds. Other USB 3.0 plugs, however, are larger than their USB 2.0 counterparts, and therefore cannot be used with older-generation ports.
USB 3.0 boasts theoretical transfer rates of up to 4.8 Gbps, or 600 megabytes per second--10 times the maximum transfer rate of USB 2.0. This would, ideally, allow you to transfer a 25GB HD movie in about 40 seconds. Pretty fast, huh?
Unfortunately, the theoretical maximum is just that--theoretical. USB 2.0 devices rarely ever reached much more than 50% of the maximum transfer rate, and it's unlikely that USB 3.0 will either. A more realistic estimate, then, is that USB 3.0 will allow transfer at up to 300-400 megabytes per second. At that rate, it would take 60-80 seconds to transfer that same 25 GB HD movie from before.
USB 3.0 hardware is still in its infancy, of course, so even 300 MB/s sustained isn't attainable yet. So far, USB 3.0 transfers top out at around 200 MB/s when using a fast external SSD. Expect that to go up in the not-so-distant future, though.
Data transfer is full duplex if it can handle data flowing in both directions (upload and download, for instance) simultaneously. A half duplex connection can only send data in one direction at a time. Think of a walkie-talkie, where you can only hear the other person as long as you're not transmitting, yourself.
Because the SuperSpeed bus uses two differential pairs to transfer data, it can transfer in both directions at the same time, making it full duplex, unlike USB 2.0.
Comments are closed on this article
tboyz124
January 09, 2012 at 12:32am
hi, will a usb 3.0 external hdd(usb powered) work in a usb 1.1 port. thanks
Philips
September 23, 2011 at 8:52pm
USB 3.0 shall be coming out soon. Many shall watch out for it. It shall be watched out.
nekollx
February 02, 2010 at 11:03am
Hell both of them are in the first page of the feature ticker
Reduddent much?
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QuakindudeMod
February 02, 2010 at 12:34pm
First off, it's "redundant", not reduddent.
Secondly, there are two different bloggers writing the articles.
Thirdly, the way these turn up in a search after Google spiders and other search engines have indexed the site leads to more traffic and that traffic finding specific information relating to their search. So if someone searches the site for USB compliant hardware articles, they will not have to read through half an article about the format itself.
Finally, the first one speaks of CES and the differences between USB standards while the second article talks about hardware that's actually available to give you that functionality. There's a reason the online Editor is in his job and believe it or not, this is how this should have been divided to present the information properly to the readers.
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nekollx
February 02, 2010 at 12:44pm
and the third one? I've read all 3 they don't really say all that much different. That's my concern, the material isn't really all that different.
------------------------------
Coming soon to Lulu.com --Tokusatsu Heroes--
Five teenagers, one alien ghost, a robot, and the fate of the world.
QuakindudeMod
February 02, 2010 at 2:38pm
The first article, posted on the first of this month by yet a third member of the blogging team, is more indepth technically than the other two articles. It obviously shows the hardware behind the format, so I had not even considered that one as part of these other two. The other two I've already explained. I see very obvious differences in all three that will appeal to a differeing group of readers and although some of the content is repeated through the three articles, you can't talk about the same thing on three differing levels without covering some of the same info.
But I'm not the official voice on how or why MaximumPC chooses to place their articles as they do. So maybe you should contact Norm since you appear to be overly "concerned" about it.
Plus, it IS USB 3.0 week at MaximumPC.
*****MaximumPC Moderator. Report inappropriate/SPAM comments to
QuakindudeMod at Gmail--dot--com with a link. My personal comments do not necessarily
reflect the opinions of MaxPC or Future US*****
nekollx
February 02, 2010 at 2:55pm
Let's just agree to disagree, it's not really worth it to contact Norm. their very similar to me but i can live with it...unlike that one article a month or so ago that was the exact same story told by 2 different people :p
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Coming soon to Lulu.com --Tokusatsu Heroes--
Five teenagers, one alien ghost, a robot, and the fate of the world.
Xerloq
February 01, 2010 at 11:16pm
I'm hoping my bet on a USB 3/SATA 6 mobo wasn't poorly placed... what have you guys seen?
dwkii
February 01, 2010 at 10:29pm
For peripherals that will be available for both connections (external hard drives, specifically), which would be faster, eSATA or USB 3.0? Are there any considerations to look at other than speed?
Digital-Storm
February 01, 2010 at 10:37pm
Sata can reach speeds of 6Gbps, USB 3.0 reaches 4.8 they said? eSata would still be faster.
Xerloq
February 01, 2010 at 11:25pm
SATA is curently divided into three revisions, SATA 1.5Gbps, SATA II (aka SATA 3Gbps), and SATA 6Gbps. The revisions/generations of SATA and their speeds are often confused because of poorly implemented marketing guidelines.
Current HDDs are SATA II/SATA 3Gbps. There's only one SATA III/SATA 6 HDD out there, and only a handful of mobos or controllers.
That means that USB 3 will be faster (theoretically) than eSATA - unless you have an eSATA enclosure that can handle a SATA III drive and a SATA III controller.
Does that mean you ditch your SATA connection for USB? No. SATA's power is in SSDs, but even then you might not max the speed.
Note, that there is no rotating magnetic media that can, alone, saturate SATA II's bandwidth - only SSDs are approaching that. The fastest magnetic media barely breaks 150MB/s (or 1.2Gbps). The Patriot Torqx drive hits 205.4 MB/s, or about 1.643 Gbps, so it'd take a couple of SSDs in RAID-0 to fill that pipe.
Crucial's launching a 355 MB/s (2.840Gbps) SSD this month. Even a pair of those won't saturate SATA 6.
So, to the OPs question, unless your external hard drive is a pair of SSDs in RAID-0, the limiting factor will be the disk, and not the channel.
