Asus P8Q77-M - Manual (Page 23)

1-13 Chapter 1: Product introduction
1.7.2 Memory configurations
You may install 1GB, 2GB, 4GB, and 8GB unbuffered 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.
• 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.
1.7 System memory
1.7.1 Overview
The motherboard comes with four Double Data Rate 3 (DDR3) Dual Inline Memory Modules
(DIMM) sockets. A DDR3 module has the same physical dimensions as a DDR2 DIMM but
is notched differently to prevent installation on a DDR2 DIMM socket. DDR3 modules are
developed for better performance with less power consumption.
The figure illustrates the location of the DDR3 DIMM sockets:
Channel Sockets
Channel A DIMM_A1 and DIMM_A2
Channel B DIMM_B1 and DIMM_B2
P8Q77-M
P8Q77-M 240-pin DDR3 DIMM sockets
DIMM_A1 DIMM_A2 DIMM_B1 DIMM_B2
• 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 2.4 Ai Tweaker menu for manual memory frequency
adjustment.
• For system stability, use a more efficient memory cooling system to support a full
memory load (4 DIMMs) or overclocking condition.