Asus X99-A Computer Hardware User Manual


 
1-8
Chapter 1: Product introduction
Chapter 1
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 conguration. Any excess memory from the higher-sized channel is then
mapped for single-channel operation.
According to Intel
®
CPU spec, DIMM voltage below 1.65 V is recommended to protect
the CPU.
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:
a) Use a maximum of 3GB system memory if you are using a 32-bit Windows
®
OS.
b) Install a 64-bit Windows
®
OS when you want to install 4 GB or more on the
motherboard.
c) For more details, refer to the Microsoft
®
support site at http://support.microsoft.
com/kb/929605/en-us.
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 efcient memory cooling system to support a full
memory load (8 DIMMs) or overclocking condition.
Always install the DIMMS with the same CAS Latency. For an optimum compatibility,
we recommend that you install memory modules of the same version or data code
(D/C) from the same vendor. Check with the vendor to get the correct memory
modules.
The design of the DIMM fan may vary. Ensure that the DIMM fan ts to the
motherboard.
Memory configurations
You may install 2 GB, 4 GB and 8 GB unbuffered and non-ECC DDR4 DIMMs into the DIMM
sockets.