Asus P9X79 LE P9X79 LE User's Manual - Page 24

Chapter 2 Memory configurations You may install 1GB, 2GB, 4GB, and 8GB unbuffered, and non‑ECC DDR3 DIMMs into the DIMM sockets. • You may install varying memory sizes in Channel A, B, C, and D. The system maps the total size of the lower-sized channel for the dual-channel, triple-channel, or quadchannel configuration. Any excess memory from the higher-sized channel is then mapped for single-channel operation. • Due to CPU behavior, DDR3 2200/2000/1800 MHz memory module will run at DDR3 2133/1866/1600 MHz frequency as default. • According to Intel® spec, the max. 64GB memory capacity can be supported with DIMMs of 8GB (or above). ASUS will update QVL once the DIMMs are available on the market. • According to Intel CPU spec, DIMM voltage below 1.65V is recommended to protect the CPU. • 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. However, there are differences in memory support specifications on 64-bit Windows OS. Please visit www.Microsoft.com for more details. 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 3.4 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 above) or overclocking condition. 2-6 Chapter 2: Hardware information