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SuperSpeed Is Faster Than High-Speed

USB 3.0 Ups Peripheral Bandwidth
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The USB Implementers Forum introduced the final USB 3.0 specification at the end of 2008. As you can imagine, the new standard once again will accelerate throughput, and although the speed bump isn’t as significant as 40x when USB 1.1 was replaced by USB 2.0, there still is a 10x increase in bandwidth. USB 3.0 is specified to run at 5 Gbit/s maximum speed. However, this increase is still great enough to offer almost twice the bandwidth of today’s Serial ATA standard (3 Gbit/s gross bandwidth).

Is 5 Gbit/s Too Much?

Every enthusiast will confirm USB 2.0 being one of the main bottlenecks in modern PCs and notebooks, as the peak net throughput typically lies between 30 and 35 MB/s. However, 3.5” desktop hard drives typically reach far more than 100 MB/s today (there even is a 2.5” notebook hard drive that can deliver this kind of throughput). Fast flash SSDs break 200 MB/s. Still, 5 Gbit/s (or 5,120 Mbit/s) equal 640 MB/s gross bandwidth. 

While we don’t expect hard drives to get anywhere near 600 MB/s within the predictable future, next-generation flash SSDs might surpass that number in only a few year's time. And this type of throughput is getting more and more important as increasing amounts of data also extend the time required to run backups. The faster your storage, the easier it is to maintain short backup windows.

Headroom For The Future

It isn’t uncommon for digital camcorders to store multiple gigabytes of video data. Moreover, the rising prevalence of HD-capable cameras will require larger and faster storage devices to handle the increasing amount of data. USB 2.0 already takes quite a while to transfer double-digit gigabyte quantities of data to a PC for editing purposes. The USB-IF shares the opinion that bandwidth remains of principle importance and expects USB 3.0 to be capable of handling all consumer devices within the next five years.

8b/10b Encoding

In an effort to ensure reliable data transfers, USB 3.0 utilizes an 8b/10b encoding, which is also being used by Serial ATA. 10-bit words are represented in a 10-bit encoding, which results in more reliable transfer at the expense of useable bandwidth. Hence the conversion from bits to bytes has to happen at 10:1 instead at 8:1.

Throughput Overview
Specification/InterfaceNominal Throughput (Mbit/s)Nominal Throughput (MByte/s)
USB 1.x1.5
0.19 
USB 1.x 121.5
USB 2.0 48060
USB 3.0 5,000500* 
FireWire 400 40050
FireWire 800 80080* 
SATA / eSATA 150 1,500150* 
SATA / eSATA 300 3,000300* 


* 8b/10b Encoding

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Top Comments
  • 16 Hide
    Casper42 , June 16, 2009 8:13 AM
    Why is it that articles like this continue to perpetuate the rumor that USB 2.0 does 480Mbps. Connect an external HDD and try copying a large file over to it. You wont see more than 35MB/s and in most cases its right around 30MB/s.

    This is because the 480Mbps (60MB/s) is for both directions AT THE SAME TIME.
    If your copying data from 1 USB device to another, this is helpful, but the fact still remains the transfer rate between the PC and either of the drives is still going to be limited to 30MB/s

    I would venture to guess that the 4.8Gbps transfer rate in USB 3.0 will be the same and therefore a file copy to/from a USB3 HDD will be limited to around 300MB/s. While this sounds great, and will likely satiate the needs of the traditional HDD market, this is basically the same speed as SATA 3Gbps that has been on the market for a few years now and will soon be replaced by SATA 6 Gbps in the next 12 months.
Other Comments
  • 1 Hide
    apache_lives , June 16, 2009 7:55 AM
    i wonder if power is still an issue with some heavy external devices (hdd's etc) - still see alot of issues even today.
  • 16 Hide
    Casper42 , June 16, 2009 8:13 AM
    Why is it that articles like this continue to perpetuate the rumor that USB 2.0 does 480Mbps. Connect an external HDD and try copying a large file over to it. You wont see more than 35MB/s and in most cases its right around 30MB/s.

    This is because the 480Mbps (60MB/s) is for both directions AT THE SAME TIME.
    If your copying data from 1 USB device to another, this is helpful, but the fact still remains the transfer rate between the PC and either of the drives is still going to be limited to 30MB/s

    I would venture to guess that the 4.8Gbps transfer rate in USB 3.0 will be the same and therefore a file copy to/from a USB3 HDD will be limited to around 300MB/s. While this sounds great, and will likely satiate the needs of the traditional HDD market, this is basically the same speed as SATA 3Gbps that has been on the market for a few years now and will soon be replaced by SATA 6 Gbps in the next 12 months.
  • -1 Hide
    bin1127 , June 16, 2009 9:02 AM
    good new, externals can now make full use of their transfer speed without SATA. Hope intel and MS implements 3.0 soon.
  • 5 Hide
    thartist , June 16, 2009 9:36 AM
    has anyone here ever had a 4mb song transfer in 0,1 secs to a pendrive?? or a 40mb album in 1 or 2 seconds?? ...i guess the chart is about theoretical limits.
  • 7 Hide
    archange , June 16, 2009 10:41 AM
    According to my book, speed is NEVER enough... So, "Is 5 Gbit/s Too Much?" - definitely not, not with the current progress rate of flash drives. Casper42 has a good point.
  • 9 Hide
    zdzichu , June 16, 2009 11:28 AM
    It would be nice to note that Linux supports USB 3.0.
  • 8 Hide
    moe2freaky , June 16, 2009 11:48 AM
    The only con I can see is that it supports 3 meter cable max. 5 meters would have been great.
  • 1 Hide
    apmyhr , June 16, 2009 12:08 PM
    I hope most external hard drives will be able to operate without AC power now. Hopefully, even the big ones. Although the increase in power sounds kind of moderate, so I wont get my hopes up.
  • 1 Hide
    belardo , June 16, 2009 1:01 PM
    The power issue with 2.5" external HDs is not so much the USB spec itself, but the chipset. Intel made the original USB, Apple made it marketable by having it on all their computers and then AMD makes it work better on their motherboards.

    I have both intel and AMD CPU/Chipsets. And noticed this at some of my clients offices as well.
    - ALL the intel systems required two USB connectors to power a 2.5" HD.
    - The AMD systems (32bit, 64bit single / dual cores) did not. A single cable works fine.

    The other issue... performance.
    When backing up Gigabytes of info... backing up about 170GB of data with an AMD64 system takes about 2hrs. With an intel Q6600/P35 (and the other Core2 systems)it takes about 5 hours! Same Ext. USB drive. It sucks... nobody has explained why this happens.
  • 1 Hide
    belardo , June 16, 2009 1:25 PM
    Ah, read more article.

    1) SuperSpeed? Just stick to the version numbers. Its easier to remember than HighSpeed and SuperSpeed... what was USB 1.1 called? Whats next, SuperDuperSpeed? Then after than, Ludicrous Speed?

    I've yet to every meet any human who called USB 2.0 as "Hi-speed".

    2) USB 1.1 was a godsend for what it did back then. Flash keys were in the mb... not GB. so it wasn't so bad. I used Firewire to xfer video to the PC. Even today, USB 2.0 is respectable even with todays HDD-Camcorders.

    It takes a few minutes to DL a 30~40mins of video recording. That is NOTHING compared to working with tape connected to an analog A/V card... even firewire from a Sony camera takes a long time (but with firewire, its perfect). 30mins of video = 30mins to convert/transfer. Having it take seconds is quite cool... in the future.

    My next PC ugprade must have (hopefully): DX-11 Video card (ATI 5850), USB 3.0, PCIe 3.0.
  • 0 Hide
    sublifer , June 16, 2009 1:28 PM
    Casper42WI would venture to guess that the 4.8Gbps transfer rate in USB 3.0 will be the same and therefore a file copy to/from a USB3 HDD will be limited to around 300MB/s.

    Read or check the spec's on USB3 before you start criticizing... they stated in the article that it supports full speed both sending and receiving. Also, USB is not limited to 30MBps in either direction, it is limited to ~60MBps combined... but is most often limited by the USB controller to sata(or IDE) interface and translation.

    I do agree that it will be too little, too late but it sounds great for now with the exception of the 3m cable limit. They really need to work on their transmission distance.
  • 2 Hide
    coopchennick , June 16, 2009 1:59 PM
    Maybe they could build a cool USB 3.0 ready computer and give it away just like they did with the SBM computers!
  • 1 Hide
    computabug , June 16, 2009 2:31 PM
    Lol maybe the USB 3.0 header on the computer is gonna get as big as an IDE connector now :p 
  • -2 Hide
    avatar_raq , June 16, 2009 2:57 PM
    I agree with Casper42, real life transfer rates never got near the advertized rates, whatever the reason is, whether it's false specification or a bottleneck with the southbridge, I don't expect USB 3.0 to be any different in that regard. In fact if the problem is a southbridge bottleneck then expect a big disappointment in motherboards supporting USB 3.0 especially the early generations.
  • -1 Hide
    bourgeoisdude , June 16, 2009 3:13 PM
    Belardo1) SuperSpeed? Just stick to the version numbers. Its easier to remember than HighSpeed and SuperSpeed... what was USB 1.1 called? Whats next, SuperDuperSpeed? Then after than, Ludicrous Speed? I've yet to every meet any human who called USB 2.0 as "Hi-speed".


    I know you haven't met me before, but for the record, I call it that.
  • 2 Hide
    descendency , June 16, 2009 4:35 PM
    I would have to imagine that USB 3.0 will be a must for Vista and a probably for XP. The userbase is just too high right now.
  • 0 Hide
    xsamitt , June 16, 2009 4:50 PM
    Or maybe call it stuper duper for those times that were drunk.
  • 7 Hide
    hellwig , June 16, 2009 5:08 PM
    Quote:
    USB 3.0 utilizes an 8b/10b encoding, which is also being used by Serial ATA. 10-bit words are represented in a 10-bit encoding

    Actually 8-bit words are represented in a 10-bit encoding. I want real-world specs. How close to 500MB/s can it really get? Also, no USB1.1 support? So I can't plug my keyboard or mouse into a 3.0 hub? I'm pretty sure my keyboard and mouse don't use the 2.0 protocol.
  • 3 Hide
    Enginerd , June 16, 2009 8:47 PM
    USB 4.0 slogan

    "We've gone plaid!"
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