Asus P5B SE User Manual - Page 34

2.4.2 Memory configurations You may install 256 MB, 512 MB, 1 GB, and 2 GB unbuffered non‑ECC DDR2 DIMMs into the DIMM sockets. Mode Single-Channel Dual-channel (1) Dual-channel (2) DIMM_A1 - Populated Populated Populated Sockets DIMM_A2 DIMM_B1 - Populated - - Populated Populated Populated DIMM_B2 - Populated • 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 DIMMs with the same CAS latency. For optimum compatibility, it is recommended that you obtain memory modules from the same vendor. • Due to chipset resource allocation, the system may detect less than 8 GB system memory when you installed four 2 GB DDR2 memory modules. • This motherboard does not support memory modules made up of 128 Mb chips or double sided x16 memory modules. • If you install four 1 GB memory modules, the system may detect less than 3 GB of total memory because of address space allocation for other critical functions. This limitation applies to Windows XP 32-bit version operating system since it does not support PAE (Physical Address Extention) mode. • If you install Windows XP 32-bit version operating system, we recommend that you install less than 3GB of total memory. Notes on memory limitations • Due to chipset limitation, this motherboard can only support up to 8 GB on the operating systems listed below. You may install a maximum of 2 GB DIMMs on each slot, but only DDR2-533 and DDR2-667 2 GB density modules are available for this configuration. 32-bit Windows® 2000 Advanced Server 64-bit Windows® XP Professional x64 Edition Windows® Vista x64 Edition 2-14 Chapter 2: Hardware information