Z77-D3H boot phase between American Megatrends logo, and 'starting windows'

[joe pineapples]

Have had two installs of W7 on the same HDD - one using GPT and the other MBR.  I noticed with GPT that the time between the American Megatrends Logo, and seeing the 'Starting Windows' message was a lot faster than with MBR, which feels like it takes an age.  Going to get an SSD soon so can't really be bothered reformatting to have the GPT option, but wondering which options (if any) could be set in the bios to speed up the initial bios boot phase?.

Also, what is 'CSM Support'(listed) in the bios?.

thanks
joe

[joe pineapples]

Guess I might have to wait till I get the SSD, but the bios shouldn't be taking this long to see the drive.  Actually attached a HDD LED now (Fractal R4 case doesn't come with one), and on initialising, the HDD light blinks for a split second then there's the pause, like the bios is checking for other devices before it continues to use the HDD to boot from.  I have the HDD as first boot device so its not that.