Asus P5NSLI Motherboard Installation Guide - Page 31

1.7 System memory 1.7.1 Overview The motherboard comes with four Double Data Rate 2 (DDR2) Dual Inline Memory Modules (DIMM) sockets. A DDR2 module has the same physical dimensions as a DDR DIMM but has a 240-pin footprint compared to the 184-pin DDR DIMM. DDR2 DIMMs are notched differently to prevent installation on a DDR DIMM socket. The figure illustrates the location of the DDR2 DIMM sockets: 128 pins 112 pins DIMM_A1 DIMM_A2 DIMM_B1 DIMM_B2 R P5NSLI 240-pin DDR2 DIMM Sockets Channel Channel A Channel B Sockets DIMM_A1 and DIMM_A2 DIMM_B1 and DIMM_B2 1.7.2 Memory configurations You may install 256 MB, 512 MB, 1 GB and 2 GB unbuffered non-ECC DDR2 DIMMs into the DIMM sockets. • For dual-channel configuration, the total size of memory module(s) installed per channel must be the same (DIMM_A1 + DIMM_A2 = DIMM_B1 + DIMM_B2). • Always install DIMMs with the same CAS latency. For optimum compatibility, it is recommended that you obtain memory modules from the same vendor. Refer to the DDR2 Qualified Vendors List on the next page for details. • Due to chipset resource allocation, the system may detect less than 8 GB system memory when you installed four 2 GB DDR2 memory modules. • If you install four 1GB memory modules, the system may only recognize less than 3 GB because the address space is reserved for other critical functions. This limitation appears on Windows® XP 32-bit operation system which does not support Physical Address Extension (PAE). • If you install Windows® XP 32-bit operation system, a total memory of less than 3GB is recommended. ASUS P5NSLI Series 1-17