Asus P9X79 PRO - Manual (Page 26)

2-6 Chapter 2: Hardware information
Chapter 2
Memory configurations
You may install 1GB, 2GB, 4GB and 8GB unbuffered ECC and non-ECC DDR3 DIMMs into
the DIMM sockets.
• You may install varying memory sizes in Channel A, Channel B, Channel C and
Channel D. 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.
• Due to CPU behavior, DDR3 2200/2000/1800 MHz memory module will run at DDR3
2133/1866/1600 MHz frequency as default.
• According to Intel CPU spec, DIMM voltage below 1.65V is recommended to protect
the CPU.
• Always install DIMMs with the same CAS latency. For optimum compatibility, we
recommend that you obtain memory modules from the same vendor.
• Due to the memory address limitation on 32-bit Windows OS, when you install 4GB
or more memory on the motherboard, the actual usable memory for the OS can be
about 3GB or less. For effective use of memory, we recommend that you do any of the
following:
- Use a maximum of 3GB system memory if you are using a 32-bit Windows OS.
- Install a 64-bit Windows OS when you want to install 4GB or more on the
motherboard. However, there are differences in memory support specifications on
64-bit Windows OS.
For more details, refer to the Microsoft ® support site at
http://support.microsoft.com/kb/929605/en-us.
• This motherboard does not support DIMMs made up of 512Mb (64MB) chips or less
(Memory chip capacity counts in Megabit, 8 Megabit/Mb = 1 Megabyte/MB).
• The default memory operation frequency is dependent on its Serial Presence Detect
(SPD), which is the standard way of accessing information from a memory module.
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, refer to section 3.4 Ai Tweaker menu for manual memory
frequency adjustment.
• For system stability, use a more efficient memory cooling system to support a full
memory load (8 DIMMs) or overclocking condition.