HP Dx5150 Hardware Reference Guide - dx5150 Microtower Model (2nd Edition) - Page 16

Hardware Upgrades DIMM Sockets The system will automatically operate in single channel mode or a higher-performing dual channel mode, depending on how the DIMMs are installed. ■ In single channel mode, always populate the XMM1 socket first. If you add a second DIMM of a different memory size than the first, install it in XMM3. Otherwise, the system will not operate. ✎ In single channel mode, the maximum operational speed is determined by the slowest DIMM in the system. If the system is populated with a DIMM that is 266 MHz and a second DIMM that is 333 MHz, the system will run at the slower of the two speeds. ■ In dual channel mode, all DIMMs must be identically matched. If you are populating only two DIMM sockets, you must use identical DIMMs and populate them in XMM1 and XMM2, the black sockets. If you are populating all four DIMM sockets, you must either use identical DIMMs in all sockets or use identical DIMM pairs in each pair of sockets, XMM1 and XMM2 black sockets and XMM3 and XMM4 blue sockets. Otherwise, the system may not operate properly. 2-6 www.hp.com Hardware Reference Guide