Asus P5N-D - Manual (Page 38)

2-14 Chapter 2: Hardware information
• 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 Vista 32-bit/Windows XP 32-bit
version operating system since it does not support PAE (Physical Address
Extention) mode.
• If you install Windows Vista 32-bit/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.
64-bit
Windows XP Professional x64 Edition
Windows Vista x64 Edition
• 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.