Just to add it is actually running slower than an identical machine using mbr
Just done a bios installation of win7 64bit and a uefi installation. uefi takes over 45 seconds. bios takes around 30 seconds. times measured from pressing power on to first appearance of desktop (with autologin).
I thought uefi was supposed to make things faster!
My Intel board with UEFI enabled, and GPT partitioned Raptor system drive, boots Windows 7 Professional in 50 seconds. The first 10-15 seconds is the BIOS start (POST) and then it goes to UEFI. My board (DP43BF) is made for a BIOS boot first (Intel makes UEFI secondary) and will always start BIOS before seeing that Windows is a UEFI load.
Until companies make UEFI only motherboards then I believe we will not see speed increases in boot times. Maybe Sandy Bridge will usher in a new era of UEFI.
If there is any way to disable the BIOS completely, I have not seen any information on it.