Asus P8B75-M LX PLUS P8B75-M LX PLUS User's Manual - Page 24

1.5 System memory 1.5.1 Overview This motherboard comes with two Double Data Rate 3 (DDR3) Dual Inline Memory Module (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_B1 Channel Channel A Channel B Sockets DIMM_A1 DIMM_B1 P8B75-M LX PLUS P8B75-M LX PLUS 240-pin DDR3 DIMM sockets 1.5.2 Memory configurations You may install 1GB, 2GB, 4GB and 8GB unbuffered non-ECC DDR3 DIMMs into the DIMM sockets. • 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. • Due to Intel® 3rd generation processors' behavior, DDR3 2250 (and above)/2133/1866 MHz memory module will run at DDR3 2200/2000/1800 MHz frequency as default. • Always install DIMMs with the same CAS latency. For optimal compatibility, we recommend that you install memory modules of the same version or date code (D/C) from the same vendor. Check with the retailer 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 3GB 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. 1-14 Chapter 1: Product introduction