EVGA Classified SR-2 Motherboard

Memory Support

Socket LGA1366 CPUs, like socket LGA1156 and AMD processors, have an embedded memory controller. All other Intel CPUs use an external memory controller, which is located on the north bridge chip (a.k.a. MCH or Memory Controller Hub) from the chipset. This means that with other Intel CPUs the chipset (and thus the motherboard) is the component that says what memory technologies and the maximum amount of memory you can have on your PC.

Since now the memory controller is inside the CPU, it is the processor, and not the chipset, that defines the memory technologies and the maximum amount of memory you can have. The motherboard, however, may have a limitation as to how much memory can be installed.

The integrated memory controller embedded in socket LGA1366 CPUs accepts only DDR3 memory (up to 1.65 V; memories that require more than that won’t work and may even damage the CPU) and supports the new triple-channel memory architecture.

The triple-channel architecture allows the CPU to access three memory modules at the same time to store or retrieve data, increasing the number of bits that are transferred per clock cycle from 128 (on dual-channel architecture) to 192. Thus this makes a 50% improvement on the maximum theoretical memory bandwidth compared to dual-channel architecture, if both are running at the same clock rate. For example, DDR3-1333 memories running on dual-channel
have a maximum theoretical transfer rate of 21 GB/s while on triple-channel they have a maximum theoretical transfer rate of 32 GB/s.

This motherboard has six memory sockets for each CPU, for a total of 12 memory sockets. The presence of six memory sockets for each CPU is a plus, because this allows you to make future memory upgrades without having to remove your current memory modules and, at the same time, to keep the maximum performance possible.

Just to clarify, in order to achieve the maximum performance you have to install three or six memory modules on each bank. If you install three memory modules you have to use sockets with the same color (on SR-2 three sockets are black and three are red). If you install a different number of memory modules the system won’t achieve its maximum possible performance.

On motherboards with only four memory sockets you have a problem: if you add a fourth memory module this module will be accessed at single-channel performance (1/3 of the maximum transfer rate) so for you to add more memory keeping the maximum performance you have to remove your old three modules and install new ones. This upgrade is more expensive than using a motherboard with six sockets, where you can simply add three more modules and keep your old modules installed.

Since today each memory module can have up to 4 GB, you can have up to 48 GB with this motherboard.

Figure 3: Memory modules. Install three or six modules on each bank for the best performance.

In summary, you will need to install at least six identical DDR3-1333 memory modules (three for each CPU) on this motherboard.