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SD Card limiting LTE Download Speeds.

Discussion in 'Android Devices' started by The Gaate, Dec 22, 2011.

  1. The Gaate

    The Gaate Lurker
    Thread Starter

    Perhaps I am overlooking something, as I don't know a ton about how android actually works. But I was looking at the speeds that people are getting with Verizon 4g LTE Service, which are well over 10mb/s. Then i was thinking, In order to write stuff that fast to a SD Card you would have to have a fairly nice SD Card, when i looked it up i saw that most Android Smart phones have around a 2mb/s SD Card. So I am thinking it stands to reason if you are trying to download stuff at a speed of over 10mb/s to a SD Card that can only write at a speed of 2mb/s. There is a bottleneck there.

    Can anyone tell me if this would actually bottleneck your speeds? Or what kind of SD Card the HTC Rezound Ships with?

    EDIT: I know that many things like aps are downloaded right to the internal storage in the phone, but if you are like me and download music and videos to the sd card. This could be a problem.

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  2. Kane5581

    Kane5581 Well-Known Member

    You rarely get downloads of more than 1mb/s on files anyway, the speed is more for how fast things load/buffer rather than files.
  3. BlueBiker

    BlueBiker Android Expert

    The confusion is because download speeds are measured in megabits (Mb/s) while SD cards are rated in megabytes (MB/s). Even the manufacturers' spec pages get the capitalization wrong sometimes.

    1 byte = 8 bits, so an inexpensive Class 2 SD card is guaranteed to be able to write 2MB/s, which comes out to 16Mb/s. I think the majority of Android phones on the market now will have Class 4 or better, which is 32Mb/s.
  4. SamXp

    SamXp Android Enthusiast

    Your SD card is not going to limit your download speeds.
  5. BlueBiker

    BlueBiker Android Expert

    Some people have reported close to 70Mb/s download speeds, so yes they can be severely bottlenecked when attempting to download large or many files onto a 16Mb/s (Class 2) card.

    You'll be limited by whatever is the slowest link in the chain: The connection, the SD card, or the particular server you're trying to download from. If you have other background apps accessing the card or the connection, that can also slow it down.
  6. SamXp

    SamXp Android Enthusiast

    Still don't buy it. The data will be processed and received by the internal cache before writing to the SD card.
  7. BlueBiker

    BlueBiker Android Expert

    Even if your phone has 1GB of RAM, probably only a small fraction of that will be available for buffering, and it won't help much if you're downloading gigabytes of movies or other media.

    But... okay I agree the limitation isn't going to be really annoying unless you frequently download huge files. Where a card's speed does matter is when capturing video or fast bursts of photos. I think the HD video recording modes require a Class 4 card or better.
  8. Padron26

    Padron26 Well-Known Member

    id have to agree with Bluebiker, not sure if any of you have ever had to download large files, i look at it like when i download multiple files to a work pc, and the hdd will get overloaded. i will have awesome download speed but my work hdd will only handle so much. because of the slow hdd.

    i will download the same files on 1 of my laptops or desktops with solid state drives or hybrid hdd's and there is no problem at all the only difference between my work and home pcs is that i have allot faster solid state and hybrid drives.

    this is pretty much the same thing as micro sd card speed ratings. compare a class 2 micro card to a class 4,6 or even a class 10. there has to be a significant difference.

    i would upgrade the speed class on you memory card if you download allot of files to your phone, but if you only download ocassionally a class 2 or 4 should be fine.
  9. maximus20895

    maximus20895 Member

    Hard drives now reach 100MB/s and low 60MB/s on average on the low side. So unless you have internet that has speeds excess of 480mb/s the hard drive shouldn't slow you down..

    The microSD classes are simple:

    Class 2 = 2MB/s
    Class 4 = 4MB/s
    Class 6 = 6MB/s
    Class 10 = 10MB/s

    Which means you will have reach these internet speeds to exceed the speed of the card.

    Class 2 => 16mb/s
    Class 4 => 32mb/s
    Class 6 => 48mb/s
    Class 10 => 80mb/s

    Keep in mind at 16mb/s is pretty fast, there are still several home networks that don't have that speed and it is faster than VZW says their LTE is (12mb/s) although I have reached 30mb/s and someone here says that they reached 60+mb/s which is just insane.

    I thought I would give everyone a perspective.

    This also changes if you are downloading do your phone as I do not even know what kind of media the phone is, it could be another card or it could be an SSD I do not know.
    SamXp and BlueBiker like this.

HTC Rezound Forum

The HTC Rezound release date was November 2011. Features and Specs include a 4.3" inch screen, 8MP camera, 1GB RAM, Snapdragon S3 processor, and 1620mAh battery.

November 2011
Release Date
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