i am currently running a cluster size of 16k (which I found to be optimal through benchmarks)...can I go back and change my stripe size and not have to reformat?...do I do this in the Raid bios or can I do it through software
No, You need first to eliminate the "old array" and to create a new one by using the utilities which are available at the bios post. The new one's will be a not partitioned and a no formatted volume. You will need to create new partitions and then you will be able to format the drives within Windows. Consequently you will lose all your data.
Principle of the highest harassment for engineers says: having two events, one bad and one favorable, with the same probability to occur, it is most probable that the bad event will occur