NVX Business Edition max RAM.

I have a ReadyNAS NVX Business Edition [X-RAID2]. Can I replace the current 1gb RAM stick with a 2gb stick? Where exactly, if at all, would doing so affect a performance boost? If anyone has done this and could tell me the make and model of the RAM stick you used I would be most appreciative.

ReadyNAS NVX Business Edition [X-RAID2]
Serial: xxxxx4RW001A9
Firmware: RAIDiator 4.2.26

Thanks in advance.