With the NF500 it depends on the raid controller that is in the system that will let you put in larger drives. So if you are using a PERC6 card in your NF500 you can change the drives and the PERC can support the larger drives.
With the NX3200 it is also just like the NF500 in that as long as the PERC card can support the raid type then the NX will also support the raid type. With the NX3200 you either have a PERC H710 or PERC H810 & those cards can create all RAID levels supported (RAID 0, 1, 5, 6, 10, 50, and 60).
Please let us know if you have any other questions.