My plan is a RAID array around 4GB. I guess with some RAID controllers (areca, maybe others?) you can change the block size to 4K so you can have up to 16TB in 32 bit windows xp. Does this work without GPT? The only other OS I would use is 64 bit xp, so would that be a better option? I would prefer to avoid switching the OS because I am currently using 32 bit xp, but I will if that's my only option.