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Power Saving Modes, New Connectors

USB 3.0 Ups Peripheral Bandwidth
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While the main goal of USB 3.0 is to increase available bandwidth, the new standard also sets its sights on average power consumption. USB 2.0 permanently polls for available devices, requiring power. In contrast, USB 3.0 was designed around four different link states, named U0-U3. The link state U0 represents an active connect, while link state U3 puts the device into suspend mode.

If a connection is idle, link state U1 will disable send and receive functions. Link state U2 goes one step further by switching off the internal clock. Connected devices hence can switch to U1 link state immediately after finishing transfers, which is expected to introduce measurable average power savings when compared to USB 2.0.

More Power

Apart from the different link states, USB 3.0 also supports higher amperage than USB 2.0. The threshold was 500 mA in the case of USB 2.0, and is being shifted to 900 mA. In addition, the amperage while handshaking the connection was increased from 100 mA with USB 2.0 to 150 mA with USB 3.0. Both stats are particularly important for portable hard drives, which often times require slightly more amperage. Previously, they had to be operated using y-cables to get power from two different USB ports while using one port for data, even though this violated the USB 2.0 specification.

New Cables, But Still Compatible

Let’s talk about cables a bit more. USB 3.0 doesn't employ fibre optics, as this would be too expensive for the mainstream. Hence, it still relies on copper cabling. But now there will be nine (instead of only four) wires. Data transfer is performed through four out of the five additional wires in differential mode (SDP--Shielded Differential Pair). One pair takes care of sending and the other handles receiving data. This is similar to Serial ATA and provides the full bandwidth in both the upstream and downstream directions. The fifth wire is the ground wire.

Color Coding

USB 3.0 is backward-compatible with USB 2.0, making the connectors appear as if they were the same as the conventional connector type A. The USB 2.0 pins remain where they are, while the five new pins were placed deep inside the connector cover. This means that you have to fully insert a USB 3.0 cable into a USB 3.0 port in order to make sure you're running in USB 3.0 mode by making the additional connections. Otherwise, you’ll fallback to USB 2.0 speed. The USB-IF recommends that all manufacturers color-code the inside of the connector cover using color “Pantone 300C.”

This is similar for the type B USB connector, although the differences are more visible here. The almost-square connectors for USB 3.0 can clearly be identified through the five additional contacts.

Mobile Device Connectors

There will be a very noticeable change for mobile devices, though. While the old Micro-B USB 2.0 connector is 6.86 millimeters wide, the USB 3.0 Micro-B type for cell phones, smartphones or media players will be as wide as 12.25 millimeters. Again, the connectors were designed in a way to maintain USB 2.0 compatibility.

Finally, cable length is going to change. While five meters were allowed for USB 2.0 connections, USB 3.0 will only support a maximum length of three meters.

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  • 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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