Dual Channel Flash Drives

With flash drives, the fewer chips you use, the smaller your device can be and the cheaper it can be as well. It is almost always cheaper for a manufacturer to use one 4Gbit flash device than to use two 2Gbit devices, so as long as there is a high enough density available, you would expect manufacturers to always opt for a single chip flash solution (at least for the memory). Lately, however, some controller manufacturers have offered "dual channel" controllers that allow you to read from/write to multiple flash devices simultaneously; think of it like RAID-0 for flash drives.


A multi-channel USB flash drive; note the presence of two flash devices to the right of the OTi controller.

Most USB flash controllers feature a single 8-bit wide interface to their flash memory, but a dual channel controller features a 16-bit wide interface and can read from/write to two flash devices at a time. Most NAND flash devices used in these drives have a 2112 byte page size, so whenever data is written, it is done in 2112 byte chunks. For a dual-channel device, all data reads and writes are effectively striped across the two memory devices, much like in a RAID-0 array.

The performance boost for a dual channel drive over a single channel drive depends a lot on the type of flash used as well as the controller itself. In many cases, however, a dual channel drive can be up to 2x as fast as a single channel drive.

Most physically larger drives that are branded as high performance drives are dual channel solutions, even if they aren't marketed as such. The cheaper drives end up being single chip/single channel, and of course, the small form factor drives end up being single chip/single channel as well.

The Performance Equation USB Flash Drive Security
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  • sprockkets - Thursday, October 6, 2005 - link

    Although not reviewed here, I got the A Data key from newegg.com simply because they say it works with Linux on the package. I know any key will, but they are the only ones to have the guts to say it. Thanks for admitting Linux exists. Lifetime warranty too.
  • jgh - Wednesday, October 5, 2005 - link

    here is a link for another link, to an app that can make many (but probably not all) usb drives bootable and a couple of other hints/tips.

    http://www.oreillynet.com/pub/wlg/5735">link

    O.T. - for some reason i get a message that says i do not have permission to access this forum when i tried to create a new login with my e-mail address. did i get banned or something? i have only posted once (it was about the gta:lcs website). i also cannot log in with the origianl user name and password.

    p.s. - it is o.k. to post links like this right?
  • Toolsac - Tuesday, October 4, 2005 - link

    I just wanna say thanks to anand for bring us all so much info on every nook and crany of computing. When ever I am getting ready to upgrade or have a problem with my computer, Anand can help me. THANKS GUYS YOU ROCK!!!
  • GameManK - Tuesday, October 4, 2005 - link

    also curious about the memorex drives like the m-flyer
  • hoppa - Tuesday, October 4, 2005 - link

    Cool article, and a nice summary of the market (the intro stuff), but seriously, who really cares that much about the perfomance of these things when the entire thing can be written or read in <1 minute anyway. I do love benchmarks though (born and will die a stat-whore)!

    I have a suggestion for the article: can you post a single picture of all the drives (preferably with a key). I'd like to see what they all look like but I wasn't too crazy at all about clicking through 20 pages. In fact, I only made it through 4.



    -andy
  • vexingv - Friday, October 21, 2005 - link

    its an iomega 256mb and claims to be usb2, but is ridiculously slow compared to a generic 64mb drive i have. i've tried transferring about 20mb worth of portable firefox on the two drives side-by-side and the iomega drive took close to 5 minutes while my other drive took less than a minute.
    these benchmarks are really useful for that purpose of finding drives w/ faster flash memory controllers.
  • Souka - Wednesday, October 5, 2005 - link

    REad the article....less than 1 min? Read it....not happening.

    Write times had the biggest delta....upto 20x speed difference....

    So would you rather watch your drive write data for 3.5mins, or almost an hour?




    Far as "clicking through 20 pages" Click once on the "Print this Article"....then you just use page down(or equivalent button) to scroll through
  • Chriz - Tuesday, October 4, 2005 - link

    This was a good roundup, but I was also curious on some other drives that can be found on Newegg. Mainly interested in the Apacer drives and also the Memorex M-flyer...which got a good review in Maximum PC because of the retractable USB connector which seems convenient to me, but I am really not sure on the performance compared to other drives.
  • intellon - Tuesday, October 4, 2005 - link

    And why was iPod Shuffle excluded? Is it cuz of security matter/ bigger size/ higher cost? Cuz I use half of my shuffle for transfering files to and from - work, home and school.
  • jkostans - Tuesday, October 4, 2005 - link

    Because its an mp3 player. There are plenty of ipod shuffle type players out there which aren't included, some smaller and more compact. I'm sure they would be with the slowest of the slow.

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