Microsoft article, "Windows Phone 7 Secure Digital card limitations, doesn’t answer the question

Microsoft has posted a Knowledge Base article, Windows Phone 7 Secure Digital Card Limitations, which seeks to explain its stance on this thorny issue. As with all things Microsoft these days, it does sheds some light but leaves the central question unanswered.

As usual, the bolded parts are mine, for emphasis.

Some Windows Phone 7 devices include a Secure Digital (SD) card slot underneath the battery cover. If you buy a Windows Phone 7 device that includes an SD card slot, you should be aware of several important differences from other devices that use SD cards:

  • The SD card slot in your phone is intended to be used only by the Original Equipment Manufacturer (OEM) that built your phone and your Mobile Operator (MO). These partners can add an SD card to this slot to expand the amount of storage on your phone.
  • To help ensure a great user experience, Microsoft has performed exhaustive testing to determine which SD cards perform well with Windows Phone 7 devices. Microsoft has worked closely with OEMs and MOs to ensure that they only add these cards to Windows Phone 7 devices.

That bit, of course, is new: We knew Microsoft tested cards. But now they are apparently OKing certain cards. I bet you can’t wait to see which ones they recommend…

Performance Requirements for SD Cards
The SD card in a Windows Phone 7 device must meet certain performance requirements for the phone to function optimally. If the SD card does not meet these performance requirements, the phone will have portions of memory that meet the performance needs of the operating system (the internal storage) and portions of memory that do not meet the needs of the operating system (the SD card). This can lead to poor and unpredictable performance when using the phone. This article uses the term Windows Phone 7 compliant to refer to SD cards that meet the performance requirements for Windows Phone 7 devices.

Determining whether an SD card is Windows Phone 7 compliant is not a simple matter of judging its speed class. Several other factors, such as the number of random read/write operations per second, play a role in determining how well an SD card performs with Windows Phone 7 devices.

And there you have it. Microsoft has identified which cards work. Microsoft has not provided that information to the public.

Round and round we go.

Thanks very much to Mike S. for the link.

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39 Responses to Microsoft article, "Windows Phone 7 Secure Digital card limitations, doesn’t answer the question

  1. clindhartsen says:

    *sigh* It’s almost like Microsoft is literally taking the secretive bit from the Apple formula these days with this. Lovely.

  2. mrtimsmith says:

    It’s a start at least…………I guess. My card works perfectly though so personally not an issue for me but I would like to see this resolved soon for the general public.

  3. commo22 says:

    This is great news. I just wish MS would have anticipated that people would be throwing in the the biggest SD cards that they could afford in there. At least they’re acknowledging the issue and it seems like they will give us a solution soon. All this and it hasn’t even been a week since it was released in the U.S. Have you heard of any international users having these kinds of issues or is it just the Samsung Focus because it has the option to install the SD?

  4. I am actually thinking about taking my Focus back over this. I definitely need more than 8 GB and I have used my exchange (iPhone 4 for Focus), so my only option is to terminate my AT&T contract on or before 11/19, which is what I will do if I don’t see a clear recommendation on cards. I’ve got another phone, so I guess I could go without for a while until they get this sorted out. I just need to return it to protect my upgrade status.

  5. dkb1898 says:

    I’m sure these cards will be available soon for a premium

  6. roteague says:

    WMPowerUser is reporting these cards as working/not working:

    I’m not not comfortable with the way this list is being compiled.

  7. damaster98 says:

    The Samsung Focus user manual (page 10) does say that Microsoft has certified SanDisk 8GB class 2 microSD card. At least that’s one that is “Windows Phone 7 compliant”.

  8. jgibo66 says:

    This is one time my procrastination has paid off

  9. BI_Tinkering says:

    Hmm, I wonder if maybe the ready boost test for PC might be a good way to test sd cards?

  10. Pingback: New Microsoft Knowledge Base Article: Windows Phone 7 Secure Digital Card Limitations

  11. gpsarakis says:

    I actually blame Samsung for this whole mess, MS had this info out more or less months ago, back at MIX if I remember right. They said that you can’t swap memory cards in and out, and that the microSD slot was so OEMs can keep costs down, you make the same model phone just use a different card for 8GB or 16GB etc.

    If you look at all the other WP7 devices out they’re very hard to get to the slot or they’re hidden under a large void sticker that says flat out not to mess with it. It sounds like it was an option the OEMs wanted so they wouldn’t have to physically add NAND directly to the devices and then jack up costs so MS did it, but it’s just for their own use. In the end, try it if you want, if it works good, if it doesn’t then it doesn’t.

  12. drewgreenwell says:

    Someone needs to let them know that this is my phone, not the oems and not the carriers. Didn’t the FCC just confirm that..

  13. drewgreenwell says:

    Additionally, I seem to have really nice os and app performance. my only speed issues seem to be with copying data to the device now that I’ve hit around 12+ GB of data. I went to put 6GB of audiobooks on my focus last night before bed(587 items). this morning (6 hrs later) there were still 447 items to be transferred. I swapped over to wifi sync this morning but it’s not helping the cause. marketplace downloads/installs have also “appeared” to have slowed down.

    I have a class 4 32GB Kingston card in my focus. benchmarking it for ready boost would have probably been a good idea(wonder if I can use parted magic or similar to reformat the card if the 16GB card I have performs better).

    I’ve downloaded two games today and both seem to have great performance still (i.e. Ive had faster level load times for harvest than I read about on other devices even though I downloaded today).

  14. dkb1898 says:

    They must have the same people writing this up, that set up the default content and marketing in the AT&T stores…I just shot you an email about how pathetic the phones seem in store because they have almost ZERO content on them…it’s really sad because it makes Microsoft seem absolutely boring and clueless. Exactly like this SD card fiasco!

    How’s your microSD card experiment going BTW Paul? Maybe part of the reason battery life has gone down on your phone?

  15. edgar says:

    after having problems with the Trascend 16GB class 6 that i bought. I went for a SanDisk 16GB class 2. And it has worked without problems except one restart that happened suddenly

  16. Well, I got my SD card from newegg today. Yep, I ordered an SD card (not micro). That is what I get for late night ordering after playing with my daughter. However, I absolutely love this phone AND it is promising that the Sandisk Class 2 card is recommended (even though at 8 GB). That leads me to think that we will be able to put in ‘recommended’ Class 2 cards at 32 GB at some point. I did not know the storage system of a mobile phone was that slow. Now, I understand why my HTC Incredible skips and pauses audio when I am doing a bunch of other stuff.

    Microsoft (and this sAMOLED screen) have impressed me. I can’t wait to see the first software update. After living with this phone for a few days, all the thoughts of possibly returning it are gone. MS is onto something here… Mind you, I am typing this on a Macbook Pro, so I have no bias.

  17. 123keith says:

    I took a gamble.
    I put in an 8 GB, Class 4 PNY brand microSD card. It has been 3 days. No bugs….yet. I post back if something goes wrong.

    • 123keith says:

      After reading the MS warning, I wanted to note that I have more that 10 GB of data on the phone. So, my data spans the internal memory and the card’s memory. This is when bugs may occur, per the article.

  18. roberthleeii says:

    My focus is working fine (knock on wood) with my 16 GB card. I have some slow syncs at times but I don’t notice it because I am usually sleeping.

    After looking at the list of cards working and not working listed above I have come up with a theory as to why some cards work and some don’t. This theory is probably way off of the mark but I am going to share it anyway. From the information gathered so far it looks like cheaper lower class cards seem two work better. I think this is the case because the memory that the phone/phones come with is cheaper lower class mass produced memory. Why put the expensive stuff in there if it is not needed or if the customer is not going to notice a difference. So when you add a card with a vastly different “speed” the OS gets confused and does not work properly. For example if you can only run a 15 minute mile (the cheaper mass produced included memory) it would be very, very hard for you to work out with a person who runs a 6 minute mile ( the class 10 card). If my memory serves right when they tore down the HD7 it had a class 2 16GB micro sd card for the main memory. If that is all it takes to run right why spend the money on faster cards.
    Or it could be what Microsoft said…
    Or Samsung…
    Or AT&T…

    • BI_Tinkering says:

      As far as the SD “Classes” go, they are all about straight reads and writes. WP7 needs better random read/write more than top end throughput. That’s one reason why I suggested using the Ready Boost test as it tests for random access speed more than pure read/write speeds.

      • mixworx says:

        Exactly. ReadyBoost needs similar performance and reliability and its test can help to decide. There is probably very few card controllers manufacturers and the bad ones simply disapear from market definitelly. Thanks, MS!

  19. metrozero says:

    I find it hard to believe these cards are “destroyed” by phone as some blogs are stating. I know the phone uses a proprietary file system to format card, but is there any way to format the sd card back to fat32 after removing from phone?
    My Kingston 16GB class 4 card is working fine, so I’m reluctant to remove it and test a fat32 format on it.

  20. Mukund Acharya says:

    I stopped by an AT&T and tried out the phones. The Samsung is a very nice one – easily my favorite. Spoke to the sales person about the microSD card and got the following “They are coming out with some kind of fix to this issue”. No idea when or if is by AT&T or Samsung or Microsoft. Or even when.

  21. Pingback: WinMo Phones - Page 31 - StrafeRight Forums

  22. AGION1 says:

    For what it is worth, I’m upset that I based my decision to purchase the Focus based on expandable memory and the fact that Samsung had sent out many tweets that Class 2 would suffice. I purchased a card and the phone based on that info. My ATT rep said nothing to me about SD problems when I purchased the phone. The info was all too late in coming. Now, I’m out of $85 and stuck with a card that cannot be repurposed. I sent an e-mail to Ballmer on Saturday. His response (“from [his] Windows Phone 7”):

    Sorry we will respond. Thanks

    Let’s hope the response is favorable.

  23. Was poking around on Sandisk’s site and found a compaitbility list where they claim to have Samsun Focus compatible cards…

  24. drewgreenwell says:

    It does look like Sandisk is the first to have cards that are guaranteed compatible.

    A certification process will help when buying new cards, but an “eject storage card” option seems like an obvious need to fix this mess. Patiently waiting for benchmarks of the 8GB sandisk card in question.

  25. Pingback: Ballmer on why breaking up is hard to do (and more Microsoft news from around the Web) | ZDNet

  26. BI_Tinkering says:

    Even when it comes to legit looking SanDisk micro SDHC cards, you have to be wary of fakes. Your best chance at having one that works is to make sure you get the exact SanDisk part number in genuine retail packaging. Cards that come in bulk packaging are more likely to be knockoffs than legit. If my order doesn’t come in retail packaging, it’s going back for sure.

  27. mixworx says:

    Anyone ever seen microSDXC card?? It will allow far better speed also, not only far more capacity, but as I know, even if WP7 host controller isnt SDXC ready, it may use it on regular SDHC max speed, if there will not be any artificial limit over 32GB in host driver or system (I dont see reason to be here…). Lets try! :-)

  28. AGION1 says:

    Paul, have you received anymore information regarding the whole SD card debacle? Above, I mentioned my e-mail to Steve Ballmer and his concise reply. Since then, I’ve been contacted a few times by one of Microsoft’s Customer and Partner Advocacy Specialists who is reportedly looking into it all further and keeping me updated as to whether or not in my situation there is anything MS can/will do for me and my card purchase. I was told that they expect some more info this week. We’ll see.

    Does anyone else have news to share?

    • Paul Thurrott says:

      No, Microsoft PR has proven worthless and is not responding to my repeated queries about this and several other topics. I’m ready to give up on these people.

      • AGION1 says:

        FYI: I was contacted by the Advocacy Specialist today and told that she had “received word back from [her] contact on [the] mobile services escalation team with some guidance on the issue…. He indicated that there are tools that can ‘recover’ the SD card and that [I] might be able to check with AT&T to see whether or not they have this tool available.” Of course she gave me no specific contact. You know as well as I that if I just randomly call AT&T the person on the other end will not know what the heck I am talking about.

        In any case, I thought I’d post this info for others in case such a tool (other than a Symbian device) exists and they can get their hand on it.

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