USB speed differences between various motherboards and BIOSses

[Kees030]

I've (had) a lot of different Gigabyte motherboards with P35, X48 and P45 chipsets. Most of them had very poor USB performance; starting Windows7 from USB took over 7 minutes. Flashing my GA-X48-DQ6 BIOS from F8D to F8i gave a huge improvement: it only took 48 seconds to start Windows 7 from USB Now I still have a GA-EP45-DS3 F10e with fast USB and a GA-EP45-DS4 F10b (F10e didn't boot and wrecked my other DS4) with slow USB. I can't figure out what causes the difference and if it's possible to fix it for the DS4.Please, someone with knowledge can compare the BIOSses and explain/fix/mod?