G5 Desktops and Leopard Server?

A friend of mine and I are both running Leopard Server on G5 desktops, and we've both independently seen very similar failures: 1. RAM failures, leading to 2. Disk corruption and even drive failure. (I lost & replaced one drive already, and now RAID says that another drive has failed.) 3. Inability to load OS X (client) (install gets about 2/3 through and then says "there's a problem, contact your software vendor.") I'm also seeing occasional errors on the TimeMachine external drive I use to back up the server. (Disk Utility's running on that right now.) Neither of us are putting much load on these machines, we're both using them as basically file/LDAP servers for other machines on the local network. Anyone else out there running Leopard Server on G5s? dave