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

[Laurent Mohin]

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
ACTERNA