Asus P9D WS, User Manual, Page: 24 / 154

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Chapter 2: Hardware information
Chapter 2
Memory configurations
You may install 1GB, 2GB, 4GB, 8GB unbuffered ECC or non-ECC DDR3 DIMMs into the
DIMM sockets depending on the installed CPU.
• 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 CPU spec, DIMM voltage below 1.5V is recommended to protect the
CPU.
• The max. 32GB memory capacity can be supported with DIMMs of 8GB.
• 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).
For system stability, use a more efficient memory cooling system to support a full memory
load (4 DIMMs) or overclocking condition.
P9D WS Motherboard Qualified Vendors Lists (QVL)
• ASUS exclusively provides hyper DIMM support function.
• Hyper DIMM support is subject to the physical characteristics of individual CPUs. Load
the X.M.P. or D.O.C.P. settings in the BIOS for the hyper DIMM support.
• Visit the ASUS website for the latest QVL.