Asus P5QC - Manual (Page 38)

2-12 Chapter 2: Hardware information
2.4.2 Memory configurations
You may install 512 MB, 1 GB, 2 GB and 4GB unbuffered and non-ECC DDR2
DIMMs or 1 GB, 2 GB and 4GB unbuffered and 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.
• For DDR2, it is recommended to install the memory modules from the black
slots for better overclocking capability. For DDR3, only install the memory
modules in the orange slots.
• Always install DIMMs with the same CAS latency. For optimum
compatibility, it is recommended that you obtain memory modules from the
same vendor.
• This motherboard does not support memory modules made up of 128 Mb
chips.
For DDR2 DIMMs:
• If you install two 2 GB or four 1 GB 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/Vista 32-bit
operation system which does not support Physical Address Extension (PAE).
• If you install Windows ® XP/Vista 32-bit operation system, a total memory of
less than 3GB is recommended.
• Due to chipset limitation, this motherboard can only support up to 16 GB
on the operating systems listed below. You may install a maximum of 4 GB
DIMMs on each slot.
64-bit
Windows ® XP Professional x64 Edition
Windows ® Vista x64 Edition
• The default memory operation frequency is dependent on its SPD. Under
the default state, some memory modules for overclocking may operate at a
lower frequency than the vendor-marked value. To operate at the vendor-
marked or at a higher frequency, see section 3.4 Ai Tweaker menu for
manual memory frequency adjustment.
• The memory modules may require a better cooling system to work stably
under full loading (4 DIMMs) or overclocking setting.