I've a following problem. I'm using STM32F427VG connected to microSD card via SDIO interface. I'm using ST driver, configured for 4-bit data access and DMA tranfer. I need to reach continuous write speed above 3000kb/sec, but the write sometimes hangs and the transfer is interrupted for more than 200msec (sometimes even 500msec), which is a problem. I've a constant data stream and I can not allocate too large buffer in a memory, because I've only internal SRAM in STM32 available (I can only accept not more than 30-50msec delay). I'm using multiple block tranfer, each block in size of 16Kb. I've tried different sd cards, but still the result is the same. If I put the card to the computer, then the write speed is much higner than 3000kb/sec and I don't expect it's a timeout generated by the card, this is too long timeout I guess.