just curious but you are able to even format the whole 3tb in your installation of windows?
i ask because windows 7 has a limit of 2.2tb using a standard bios.
If your os was installed using efi i would say ok fine but the ps3 uses a 16bit bios anyway which is why it has a limit of 2.2tb as well.
efi, removes the bios limitation on drive sizes, 16bit bios is being phased out due to those limits at 2.2tb, the actual bios is a 64 bit program installed on your harddrive instead of flash memory on your mobo.
while windows 7 64 is a good os it has it's limits on drive size defined before it can even load up by the bios, the ps3 is no different in that regard those limitations are there and there is no way around them without changing the hardware to support larger drives.