The disks would need to be GPT rather than MBR and you need an EFI BIOS to be able to boot from a volume this size.
Better if you create a 1TB partion for the os/ and the rest for data, then W7 should be ok to boot.
I have a g1 sniper motherboard and ended up MBR the two 2tb green hd in raid 0 on the 6gb/s sata conn of the motherboard it sees 3.7tb in win7. lost about 300gb , good enough. use for running games and storage.
i have two xm25 intel 80gb ssd running in raid 0 on the 3gb/s sata conn of the motherboard 160gb boot drive loads win7 in 9 sec i also use this drive to run all my primary software, adobe an such.
i was not sure if win7 would see the whole 4tb and after making the raid 0 in win7 it will only see 3.7tb.