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stm32f4 board, slow writing issue on SDIO interface

Question asked by sibghatullah.ahmed on Sep 16, 2013
Latest reply on Sep 18, 2013 by sibghatullah.ahmed
Dear All,
               I am working on SDIO interface of STM32F4_discovery board using mass storage class example (dated: 05-March-2012). By going through different posts (special thanks to clive1) i have now been able to achieve undermentioned performance with perfect/reliable read and write.
Read: 3.66MBps
Write: 1.2MBps

on 8GB class 4(Sandisk), 8GB class 10(Tanscend) card,  SDIO_CLK = 24MHz and card is FAT32 formatted
After that I have tried every possible effort to increase the speed atleast up to 5MBps (as claimed in different posts) but all in vain.Using different speed grade cards is also not helping. I am using MultiBlock write command with Pre-Erased (ACMD23) functionality. Any suggestion to improve the speed would be highly appreciated.