Asus P7P55D Premium - Manual (Page 31)

ASUS P7P55D Premium 2-11
Chapter 2
2.4.2 Memory configurations
You may install 1GB, 2GB 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.
• According to Intel spec definition, DDR3-1600 is supported for one DIMM per channel
only. ASUS exclusively provides two DDR3-1600 DIMM support for each memory
channel.
• According to Intel CPU spec, DIMM voltage below 1.65V is recommended to protect
the CPU.
• According to Intel CPU spec, CPUs with a core frequency of 2.66G support the
maximum DIMM frequency of up to DDR3-1333. To use DIMMs of a higher frequency
with a 2.66G CPU, enable the DRAM O.C. Profile feature in BIOS. Refer to section
3.5.1 Ai Overclock Tuner for details.
• 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.
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 3.5 Ai Tweaker menu for manual memory
frequency adjustment.
• For system stability, use a more efficient memory cooling system to support a full
memory load (4 DIMMs) or overclocking condition.