Asus M5A78L-M PLUS/USB3 M5A78L-M PLUS/USB3 Users manual English - Page 16

System memory Overview This motherboard comes with four Double Data Rate 3 (DDR3) Dual Inline Memory Modules (DIMM) sockets. A DDR3 module has the same physical dimensions as a DDR2 DIMM but is notched differently to prevent installation on a DDR2 DIMM socket. DDR3 modules are developed for better performance with less power consumption. The figure illustrates the location of the DDR3 DIMM sockets: DIMM_A1 DIMM_A2 DIMM_B1 DIMM_B2 Channel Channel A Channel B Sockets DIMM_A1 & DIMM_A2 DIMM_B1 & DIMM_B2 • You may install varying memory sizes in Channel A and Channel B. The system maps the total size of the lower-sized channel for the dual-channel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation. • Always install the DIMMS with the same CAS Latency. For an optimum compatibility, we recommend that you install memory modules of the same version or data code (D/C) from the same vendor. Check with the vendor to get the correct memory modules. • Due to the memory address limitation on 32-bit Windows® OS, when you install 4GB or more memory on the motherboard, the actual usable memory for the OS can be about 3GB or less. For effective use of memory, we recommend that you do any of the following: - Use a maximum of 3 GB system memory if you are using a 32-bit Windows® OS. - Install a 64-bit Windows® OS if you want to install 4GB or more on the motherboard. - For more details, refer to the Microsoft® support site at http://support.microsoft. com/kb/929605/en-us. • This motherboard does not support DIMMs made up of 512Mb (64MB) chips or less. Visit the ASUS website at www.asus.com for the latest QVL. 1-8 Chapter 1: Product introduction