The drives are connected to the motherboard, so each drive maxes out at 600MBps, not the whole array. To saturate the connection each drive would need to have over 600MBps read/write. The individual connection, not the total is the limiting factor. That said, RAID 0 on SSDs is an exercise in epeen waving. The risk of losing your data is increased and you lose TRIM, so I would say it is kind of pointless...unless you genuinely put massive files on your SSD as your main storage and can't wait for the transfer times.