AMD CPUs have an embedded memory controller, meaning that 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.
Even though it is not a socket AM3 motherboard, the ASRock N68C-S UCC supports DDR3 memories (blue sockets). It is very important to keep in mind that you have to choose between one or the other. You cannot use DDR2 and DDR3 modules at the same time, and you can install DDR3 memories only if you install a socket AM3 processor on this motherboard. If you install a socket AM2 or AM2+ CPU, it won’t recognize DDR3 memories.
The maximum memory speed you can install will depend on the CPU you have. Current AMD CPUs support DDR2 memories up to 1,066 MHz, but older CPUs can only recognize memories up to 800 MHzm, even if you install DDR2-1066 memories.
At the moment, the integrated memory controller of socket AM3 processors supports only DDR3 memories up to 1,333 MHz; however, ASRock says, the N68C-S UCC supports DDR3 memories up to 1,600 MHz through overclocking.
The motherboard supports the dual-channel feature, so you should install two identical memory modules (either DDR2 or DDR3), in order to achieve the maximum performance your motherboard can provide.
The reviewed motherboard has two DDR2 (yellow) and two DDR3 (blue) sockets, and at the moment, each memory module can have up to 4 GB, allowing up to 8 GB for this motherboard (since you can’t use DDR2 and DDR3 sockets at the same time).
The first and third sockets are blue and reserved for DDR3 modules, while the second and fourth are yellow and reserved for DDR2 modules.