For Gigabyte motherboards, you can enable change full support to partial support for USB in the BIOS setup, so USB mouse and keyboards will be connected, but not USB external drives.
Edit: that was not enough, I still could hear BIOS got stuck there waiting for my USB hard drive powering up. So In USB configuration, I disabled mass storage support, so bios ignores USB drives. Don't worry, you will still see your usb hard drives after windows loads.