My RevA G5 iMac was recently replaced with a RevC 1.9GHz iMac G5 by Apple. When I first got my iMac G5 (RevA) I spent nearly $200 on a 1GB stick of RAM. Will this RAM work in my new iMac G5 (RevC)? If so will there be much of a performance impact by using the less capable RAM (1GB) with the pre-installed newer RAM (512MB)? Thanks!