Asus P5B-MX/WIFI-AP - Manual (Page 30)

1-18 Chapter 1: Product introduction
• 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.
• If you install two 1 or 2GB memory modules, the system may only recognize
less than 3GB 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.
• This motherboard does not support memory modules made up of 128 Mb
chips or double sided x16 memory modules.
Notes on memory limitations
• Due to chipset limitation, this motherboard can only support up to
4 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 64-bit
Windows ® XP Windows ® XP x64 Edition
Windows ® 2003 server Windows ® 2003 server x64 Edition
• Some old-version DDR2-667 DIMMs may not match Intel ® ’s
On-Die-Termination (ODT) requirement and will automatically downgrade
to run at DDR2-533. If this happens, contact your memory vendor to check
the ODT value.
• Due to chipset limitation, DDR2-667 with CL=3 will be downgraded to run
at DDR2-533 by default setting. If you want to operate with lower latency,
adjust the memory timing manually. There will be 4MB reduction in total
memory when enabling ASUS Thermostat function under Single Channel
mode, and 8MB reduction under Dual Channel Mode.
• The total memory may has 4MB reduction under Single Channel mode, and
8MB reduction under Dual Channel mode because the address space is
reserved for Intel® Quiet System Technology.