Asus P7H55-M/USB3 - Manual (Page 28)

1-15 Chapter 1: Product introduction
1.7.2 Memory configurations
You may install 512MB, 1GB, 2GB, and 4GB unbuffered non-ECC DDR3 DIMMs into the
DIMM sockets.
• 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 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.
• 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.
• Due to Intel spec definition, X.M.P. DIMMs are supported for one DIMM per channel
only.
• 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 2.66GHz support the
maximum DIMM frequency of up to DDR3 1333. To use DIMMs of a higher frequency
with a 2.66GHz CPU, enable the DRAM O.C. Profile feature in BIOS. Refer to section
2.4.1 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.
• This motherboard does not support DIMMs made up of 512Mb (64MB) chips or less.
• ASUS exclusively provides hyper DIMM support function.
• Hyper DIMM support is subject to the physical characteristics of individual CPUs.
• 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.
• Visit the ASUS website at www.asus.com for the latest QVL.