Have a Dell 8300 - Win 7 Ultimate 64 bit - i7 -3.40 Ghz processor - 8 Ghz ram - trying to install a Toshiba 3tb HDD as a secondary (2nd) non-boot drive...the AO6 bios recognizes the full 3Tb drive and so does the Intel Storage Controller at 2+ TB. I can't get it above 746 Gb...what am I doing wrong?