I'm currently running Android on my HD2 using the internal memory. However I'm having terrible issues with the memory filling up and I can't seem to solve it. I considered installing Android directly onto the SD card, but was told by a friend that it would slow down the OS so bad that it would hardly be possible to use.

So my question here is quite simply; will there be much performance impact by running Android from an SD card?

Adding bounty now, due to lack of patience.

  • I'm looking for an answer derived from personal experience or believable online sources
  • I won't accept probablies and maybes
  • 3
    The SD Card's performance class will also have a dramatic impact on the performance you experience. Commented Jun 16, 2011 at 20:54

7 Answers 7


Quite a few people dual boot Nook Colors (internal vs sd card).

Take a look at this xda thread on running CM7 on the sd card (for the Nook Color) and this thread about booting from sd card performance.

In short, it really depends on the read/write abilities of the sd card you use. A crappy sd card is going to give crappy performance.

(Sorry for the specifics to Nook Color, but in general, it should be similar)


According to this article there's a dev over at XDA by the name of DarkStone1337 who built a custom ROM built on Android 2.2 which is designed to run entirely from a HTC HD2's RAM.

They claim it's super fast. I know it's not precisely what you're looking for, but I'd read into that and give it a shot if you're so inclined.


I have run android from nand and from the sd card. In general performance was better running from nand. However I was recently using American Android on sd and performance was fine. Sense based roms still seem to drag running from sd but non sense roms now seem ok.

You can test it out without blowing away your current install. Just download a magldr rom, put it in the android folder on the sd card, reboot into magldr and tell it to boot android from SD.

Also, use a quality sd card, not a no-name one. Makes a big difference.


I installed NexusHD yesterday on my HD2 with DataToExt and must say, it is not slower but at least a bit faster than before, when I installed it only on NAND (internal space).

But the performance depends on the class of the SD card. If you have an SDcard greater than class 6 you're good to go, beneath there, you should buy a better one (8gb class 10 is really cheap, even the top manufacturer).

But you should format your card for that. To know how, use this tutorial: http://forum.xda-developers.com/showthread.php?t=916464


For what I understand from your question, you have the Android ROM installed on the internal memory of your phone and you are running out of space. If this is the case, have you tried to partition the SD card and use some tool like S2E to increase the amount of available memory without moving the ROM to the SD card?

In my case I have a phone with 512Mb of internal ROM and when I install a custom ROM, it leaves me about 100Mb to install applications. In order to increase this amount of available ROM space for applications I partitioned the SD in 2 primary partitions, one 512Mb EXT3 and one FAT with the rest of the space on the SD Card. With the partitions and the phone rooted I installed an App called S2E that allows your phone to use the EXT3 partition on your SD card to install applications.

With this configuration I maintain the base system (Android and Google applications) on the main ROM of the phone, while all other applications are installed on the EXT3 partition of the SD card, giving me more room for applications and avoiding the inconvenient of having to move all the Android system to SD card.


I have done this and was a bit worried about the low internal memory that is left. I added the app "App2sd" from the marketplace and it looks at your apps and tells you which can be saved on the SD card instead of the internal memory. This has meant that almost all of my apps have now been moved onto the SD card, freeing up space in the memory for apps that can't be moved.

  • 5
    Doesn't answer the question
    – Pitto
    Commented Jun 13, 2011 at 11:05
  • Also perhaps I wasn't clear on exactly how much space I have left. It's not enough for a few hours of SMS. I don't even have room to install the smallest of applications.
    – Hubro
    Commented Jun 16, 2011 at 14:36

Hey Guys Im running Android on my SD Card on the HTC HD 2 without a single Glitch but after trying out several builds of Android. I finally got one that works just fine and i haven't had any problems with it running on my SD card.

Performance and Speed is super. All my mails are poped (thats three mails). Im really happy with it.

and like Bryan said it also depends on the read/ write speed of your SD card and he is right coz i had that exact problem I used a bad SD Card till i got a proper one.

So the SD Card quality really daz matta too.

  • 1
    Despite having enough relevance to the original post, this still looks like an automated spam response.
    – crdx
    Commented Jun 22, 2011 at 14:59

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