That time period saw the Intel 5000, 5100, 5200, 53 processors. The HP ProLiant G5-series of server were long-lived, coming out in 2006 and hitting end-of-life in 2009. You probably won't be able to accept the CPUs and RAM you want in the system you have now. Those supported the Intel 5100-series CPU you have now. The initial G5 servers were introduced in late 2006 with the Intel 5000Z chipsets.
There were two system chipsets sold with this series of server.
