[U-Boot-Users] why is USB so slow

VanBaren, Gerald (AGRE) Gerald.VanBaren at smiths-aerospace.com
Tue Jan 13 15:00:39 CET 2004

IDE = 16 parallel bus (8MHz? => 128Mbits/second with very little overhead)

USB = serial bus with a lot of overhead
  USB-1.1 == 12Mbits/second
  USB-2.0 = 480Mbits/second

I'm guessing you are running USB-1.1 based on your numbers.


> -----Original Message-----
> From: u-boot-users-admin at lists.sourceforge.net
> [mailto:u-boot-users-admin at lists.sourceforge.net]On Behalf Of Laurent
> Mohin
> Sent: Tuesday, January 13, 2004 2:33 AM
> To: U-Boot-Users at Lists. Sourceforge. Net
> Subject: [U-Boot-Users] why is USB so slow
> Hello all,
> I want to submit a question about USB performance.
> I'm designing a board with a 405GPr and an Intel PIIX4E Southbridge. 
> For upgrade purpose, I'm dowloading linux and initrd image 
> which size is 
> about 9M bytes.
> With a compact flash on the IDE bus, I issued the command :
> fatload ide 2:0 800000 pMulti
> and had the file downloaded in 10 seconds
> With a memory key on the USB bus, I sent the command :
> fatload  usb 0:0 800000 pMulti
> and had the file downloaded in 150 seconds
> Has somebody else noticed this behaviour? What is the explanation?
> Laurent MOHIN
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