Hi, In order to optimize the BIOS of the ASUS P7P55D-E PRO motherboard, I'm looking for information about the USB functions. Here is what the manual says : (I cannot post any images, urls, ...) USB Functions [Enabled] [Enabled] Enables the USB Host Controllers. [Disabled] Disables the controllers. (the two following items appear only when you set USB Functions to [Enabled]) Legacy USB Support [Auto] [Auto] Allows the system to detect the presence of USB devices at startup. If detected, the USB controller legacy mode is enabled. If not, the legacy USB support is disabled. [Enabled] Enables the support for USB devices on legacy OS. [Disabled] Disables the function. BIOS EHCI Hand-off [Enabled] [Enabled] Enables the support for OS without an EHCI hand-off feature. [Disabled] Disables the function. There is no literature on the net about this subject. Firstly, Windows 7 fully support USB 2.0 and EHCI is for USB 2.0 support so is it necessary to enable that function ? I read that it could be responsible for a long-time boot if it was enable with a few models of motherboard. I read something about it on this forum but it was not very detailed. Secondly, giving that I have almost never a USB device connected at startup, can I safely disable Legacy USB Support ? It is said in the following article that it is useful when OS do not natively support USB. So when Windows 7, is it always useful ? "This BIOS feature determines if the BIOS should provide legacy support for USB devices like the keyboard, mouse and floppy drive. This is a useful feature when using such USB devices with operating systems that do not natively support USB (e.g. Microsoft DOS or Windows NT). When enabled, the BIOS will enable legacy support for USB keyboards, mice and floppy drives. You will be able to use these USB devices even with operating systems that do not support USB. When disabled, the BIOS will not enable legacy support for USB keyboards, mice and floppy drives. You will not be able to use these USB devices with operating systems that do not support USB. However, the BIOS can only provide relatively rudimentary support. For full functionality, you will need to use an operating system that supports USB and install any necessary driver. Alternatively, you can also enable the USB Port 64/60 Emulation BIOS feature." Thanks a lot for your help !