Intel socket LGA1155 CPUs have an embedded memory controller, meaning that it is the processor, not the chipset, that defines what memory technologies you can have and the maximum amount of memory that is possible. The motherboard, however, may have a limitation as to how much memory can be installed.
The integrated memory controller from socket LGA1155 processors supports DDR3 memories up to 1,333 MHz (“Sandy Bridge” CPUs) or up to 1,600 MHz (“Ivy Bridge” CPUs). According to ASRock, the Z77E-ITX supports memories up to 2,800 MHz.
The ASRock Z77E-ITX has two memory sockets. Since DDR3 memory modules can be found in capacities up to 8 GB, you can have up to 16 GB with this motherboard if you use two 8 GB modules.
In order to enable the dual-channel mode, you must install two memory modules.