I found out my motherboard, an Intel DP35DP has a UEFI firmware that defaults to booting with BIOS emulation.
I've done that. If you try this, ensure you're using a recent BIOS, since Intel's 3-series motherboards had pretty broken support
around this time last year.
One of the problems with these motherboards is that they only have a 4 Mbit EEPROM flash chip, with the result that you won't be able to install to any drives in AHCI or Native IDE mode
. You'll need to switch the SATA controller to legacy mode (so that the int 0x13 interfaces are available), since that is the only mode the UEFI firmware supports for UEFI boot. (The upshot of this is that when you boot up the Vista x64 SP1 installer with UEFI Boot turned on, it will refuse to install to any drives in AHCI or Native IDE mode, complaining that the system cannot boot off them, which it really can't.)
This of course also means no firmware RAID support for UEFI boot.
Another issue is that the EFI boot list in the NVRAM takes precedence over the boot order you specify in the BIOS setup. So if you have installed Vista x64 SP1 in UEFI mode, the installer places an entry in the EFI NVRAM that causes the motherboard to boot off it. If you now wipe
the drive, at least with older BIOSes you couldn't boot at all
unless you used the F10 key to explicitly pick a device every boot. Someone ran into this problem and PMed me on the Ars forums. At that point even if you try to boot off the Vista installer DVD, it won't bother booting off it. This issue persisted even if you turned off UEFI Boot in the BIOS setup.
It's my understanding that the last few BIOSes have this problem fixed, and now if the EFI boot list doesn't have any valid entries it'll proceed with legacy BIOS boot instead.
The 4-series boards from Intel have a four-times larger flash chip (32 Mbit), and their UEFI boot firmware does support booting off AHCI and I think RAID. With the 3-series boards I was rather disenchanted with the lack of support.
(In particular, I'm a Linux user, and trying to dual-boot Linux with Windows in UEFI mode would require the use of a UEFI shell, since Linux would also have to do UEFI boot, and the only UEFI bootloaders available for Linux need to have entries explicitly placed for them in the EFI NVRAM boot list via an EFI shell. Unlike the Windows installation DVD-ROM, Linux distros still don't have UEFI-enabled boot images that can start the installer via UEFI and thus be able to manipulate the EFI boot list to add an entry. The Intel desktop boards all lack an EFI shell altogether, so Linux cannot be installed on them via UEFI boot. So I found the UEFI support on my DG33FB−which uses the same firmware as your DP35DP−to be rather underwhelming.)
Good luck if you decide to experiment with it.