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How do I low level format a microSD card for my Android phone ?

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February 27, 2011 10:58:37 PM

Hi guys ... So recently I purchased this 16 GB micro SDHC card for my new Android phone:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

The problem is that I'm not getting the 4 MB/sec write rate that this card promises ... I tried low level formatting it with this tool:

http://hddguru.com/software/2006.04.12-HDD-Low-Level-Fo...

.... but the write-rate is still the same .. Both before and after trying to low level format the card, I'm getting a write-rate of about 0.9 MB/sec ~ 1.0 MB/sec ...

Other people who have purchased this card from Newegg have said in their feedback that they can at least achieve 3 MB/sec or something, and I'm not even close to that .. Am I doing something wrong ?
a b G Storage
February 28, 2011 2:04:58 AM

What phone are you using, and how are you calculating the transfer rate?

What devices are the other people using to read that card? <- that's going to be the kicker, you can't compare a card reader connected by usb to the internal transfer rate of your phone.

Also, what filesystem do you have on the card. I can't recall if I've ever pulled my card and read it from my computer, but I believe that it should be formatted EXT3, which is a linux filesystem. Most SD cards being used by PC's have either FAT32 or maybe NTFS on them to be read by windows.
February 28, 2011 6:13:44 AM

Do you say about SDHC speed Class4?
Both SD card, and host should support it. If this 1MB/s transfer rate is true
its phone does not support HS mode. Mobile phone can not often use high
tranfser rate mode for battery-life.

Regarding file sytems, SD specification of Speed Class4 is for only FAT
file system that is specified by SD. If you uses other file system on SD card, 4MB/s transfer rate is not guaranteed. (It is not said that transfer rate is less than 4MB/s if other filesystem)

Regarding low-level format, this software is not significant for SD card.
Low-level format for SD card is none. If you specify about erase-command,
you should use SD FormatterV3( Down load SD Formatter V3 from http://www.sdcard.org/comsumers/formatter_3/) and SD Reader/Writer that
supports CPRM. But tranfer rate may be unchanged after erase-command.

Related resources
March 5, 2011 10:37:37 PM

Er, no .. I actually meant to say that I am using my PC to do the low level formatting, and the 1 MB/sec rate I'm getting is when read/writing a PC .. I haven't tried the card in my phone yet ..

I'm using the microSD -> SD adapter which came with the microSD card itself, and then putting this SD adapter into my laptops builtin card reader ... Is there any problem with this setup ?
March 8, 2011 2:20:42 PM

ahmadka said:
Er, no .. I actually meant to say that I am using my PC to do the low level formatting, and the 1 MB/sec rate I'm getting is when read/writing a PC .. I haven't tried the card in my phone yet ..

I'm using the microSD -> SD adapter which came with the microSD card itself, and then putting this SD adapter into my laptops builtin card reader ... Is there any problem with this setup ?


What is Low-Level format? There is no low-level format in SD specification. In HDD, and DVD-RAM these can be formatted, but SD card can be overwrite-formatted with/without erase-command. Which software do you use for low-level format?

If you formatted SD card by SD Formatter V3.0 or V2.0, and trasfer rate is 1MB/s, it may be for this reason that
1. SD card reader in your PC is not supported High Speed Mode in SD Specification. Please try other SD card (with speed class 4).
2. SD card reader in your PC and this SD card is not compatiblity.

SD adatapter(microSD->SD) does not affect transfer rate if the adapter is standardized. (in market there are some unstandardized adapter).

!