Because DFI designs their boards for the extreme 10% of gamers/enthusiasts, and not the other 90% like Asus orgigabyte or msi might do. DFI boards have been known to have problems with certain types of ram... namely corsair and certain PSU's. It just comes with the territory, the DFI bios is heavily optimised, and the power cercuitry is designed to be overclocked and some PSU's are not up to snuff.