Core i7 CPUs have an embedded memory controller, just like it happens with AMD processors. 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. 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 Core i7 integrated memory controller accepts only DDR3 memory (up to 1.6 V; memories that require more than that won’t work and may even damage the CPU) and supports the new triple-channel memory architecture. Even though first Core i7 CPUs officially support up to DDR3-1066, EX58 Extreme supports up to DDR3-2100 (ASUS P6T Deluxe supports up to DDR3-1600 memory and Intel DX58SO "Smackover" supports memory up to DDR3-1333).
The triple-channel architecture allows 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.
One of the highlights of the Gigabyte EX58 Extreme is the presence of six memory sockets, not just four, as in Intel DX58SO. With this feature you can make future memory upgrades without having to replace your current modules, while maintaining the maximum possible performance.
For maximum performance with Core I7 processors you need to install three or six memory modules. If you install three modules you must to use sockets with the same color (three sockets on EX58 Extreme are green and three are pink). If you install a different number of memory modules your PC won’t achieve the maximum possible performance.
On a motherboard with only four memory sockets you have a problem: if you install a fourth memory module, it will be accessed with the performance of a single channel (1/3 of the maximum transfer rate), so for you to install more memory maintaining maximum performance you must remove your old modules and install three new modules. This upgrade is more expensive than using a motherboard with six sockets, where you can simply install three additional modules and keep your old modules installed. Gigabyte EX58 Extreme accept up to 24 GB, while ASUS P6T Deluxe supports up to 12 GB and Intel "Smackover" supports 16 GB.
Next to the memory modules X58 Extreme has on/off and reset switches, feature found only in motherboards targeted to enthusiast users.