How to increase SD card read speedTips


Last Updated: 2011-04-07 11:28:22
  1. Usta

    Usta Well-Known Member

    There is a topic in XDA, which suggests a way to increase the SD card's speed by increasing the cache size.

    You can check your SD cards' cache size by opening this file: /sys/devices/virtual/bdi/179:0/read_ahead_kb



    Read more about it here: [Script][CWM] SD Card reading speed fix - xda-developers

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  2. SUroot

    SUroot Well-Known Member Developer

    There is a proviso here, that you are rooted and your rom has init.d support btw
  3. formicae

    formicae Well-Known Member

    There's also no evidence that this has any practical benefit. Having it benchmark faster in a specific app, and reports of the gallery "loading way faster" aside, real-world speed increases seem to be nil, or negligible at best. It's just changing the way the phone interfaces with the SD card in a way that tricks the benchmark.

    I also have an external USB hard drive that reports its read speed in Windows as ~150 megabytes per second for the first few seconds of a file copy -- at over a gigabit per second, this is more than twice as fast as USB2 can actually feed data to the computer. The SATA-to-USB interface on the drive is simply providing confusing data to my PC when it starts sending data. I suspect this is what's happening with the Android 'speed fix.'
  4. SUroot

    SUroot Well-Known Member Developer

    Although from benchmarking perspective, it tricks the results in a way, but the read ahead itself does have genuine advantage sometimes.

    The read ahead whilst using a2sd for me seems to speed up time between boot and the phone being usable, which is worth it alone.

    Have I noticed any other improvements except for start up time? No.
  5. formicae

    formicae Well-Known Member

    Hm, maybe I'll give it another shot. I tried it at 2k and didn't notice any real difference, maybe I'll try 3k -- speeding boot up would be pretty great.

    But yeah, it's definitely not the magical speed elixir so many people seem to be claiming on the XDA thread.
  6. SUroot

    SUroot Well-Known Member Developer

    Nothing ever is. There are tweaks that can improve somethings via software, but there is always a hardware limitation.

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