SD catd slot speed

Discussion in 'EP121 Slate' started by kwg06516, May 22, 2011.

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  1. kwg06516

    kwg06516 Pen Pal - Newbie

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    Thanks for all the replies, everybody. Jury duty got cancelled today so I'm haring fan with my new machine.

    If an SD card will play an HD movie without lag then it is more than sufficient for my needs.
     
  2. YetAnotherDave

    YetAnotherDave Pen Pal - Newbie

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    From what I understand, the SD card reader is hooked to the system via an internal USB (2.0) controller. Although I haven't tried benchmarking it, I wouldn't expect more than USB2's 10MB/s maximum transfer rate, no matter what SD card you use.

    Streaming 1080p requires about 10MB/s in typical scenarios, and in my experience this is just barely sufficient to stream without unacceptable glitching.

    Using the bundled Atheros WiFi adapter with with it's 150(N) max transfer rate, for example, I get about 8-10MB/s, which if I allow the player to buffer for a while, does provide a barely acceptable streaming experience.

    So I'd suggest passing over the SDXC cards (as you figured out) and go for the highest capacity SDHC card you can. I usually opt for class-10 cards so they're compatible with my HD camcorder as well.

    But in any case, I would not recommend anyone try to run applications from a USB2-connected device unless they like waiting.

    [My first computer was a 1982 home-made Z80 Steve Ciarcia-special ;-)]
     
  3. douglucas

    douglucas Pen Pal - Newbie

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    I use a 32gig PNY 20MB/s SDHC for my main document/file storage. I even run 3 *programs* from it (executables). All I know is -- I've owned computers since 1983 and I can't detect any speed difference in "real world computing" when accessing the internal drive vs. accessing the SDHC drive.
     
  4. daveyd007

    daveyd007 Pen Pal - Newbie

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    I bought a 32GB PNY Class 10 SDHC card for expanded onboard storage. Copying data from an external 80GB, Intel X25-M SSD (via SATA to USB 3.0 cable) to the PNY SDHC card, I get a Continuous Minimum Write of 13.5mb/sec. I get the same minimum write speed copying from the C Drive to the SDHC card.

    From the slate's SSD to the external Intel X25-M USB SSD, I get 20mb/sec Continuous Minimum Write going out. (Since the 80GB X25-M SSD can perform faster when tethered to my homepc with USB 3.0 at 70-110Mb/sec WRITE, this is possibly the fastest data output option, limited via usb 2.0 connection on the slate.) Now, from the USB Intel SSD to the on-board msata, copying is a minimum 25mb/sec continuous write.

    SpeedWise- Working with the sdhc card as my program file folder is fine, and bearable. HD videos don't have any visual lag while playing them. Ditto for the ssd on a usb connection.
     
  5. krfighter

    krfighter Scribbler - Standard Member

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    just my 5cents, but as I mentioned in other threads I tried 45mb/s Sandisk card and it would never give me better than 20 MB/s
    Sold it and bought a cheap Transcend. No difference on this tablet
     
  6. douglucas

    douglucas Pen Pal - Newbie

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  7. dumining

    dumining Pen Pal - Newbie

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    I came across this thread after having issues after moving a Calibre library to a SDHC card, on updating a books metadata it goes 'not responding' for 60secs before the software moves on (ie while it is updating database files etc) -

    Patriot LX series class 10 - 32GB SDHC
    tested using AS ssd benchmark AS SSD Benchmark thread

    AS SSD Benchmark 1.6.4237.30508
    ------------------------------
    Name: Multiple Card Reader USB Device
    Firmware: 1.00
    Controller:
    Offset: 4096 K - OK
    Size: 29.88 GB
    Date: 30/01/2012 4:02:12 PM
    ------------------------------
    Sequential:
    ------------------------------
    Read: 16.41 MB/s
    Write: 8.30 MB/s
    ------------------------------
    Access Times:
    ------------------------------
    Read: 3.692 ms
    Write: 17.971 ms

    It doesnt appear to live up to Class 10, and SSD comparison below, but I would like to get more out of some sort of removable storage?

    AS SSD Benchmark 1.6.4237.30508
    ------------------------------
    Name: SanDisk SSD P4 64GB
    Firmware: SSD
    Controller: iaStor
    Offset: 1024 K - OK
    Size: 59.62 GB
    Date: 30/01/2012 10:41:03 PM
    ------------------------------
    Sequential:
    ------------------------------
    Read: 123.43 MB/s
    Write: 13.57 MB/s
    Access Times:
    ------------------------------
    Read: 0.700 ms
    Write: 1.010 ms
     
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