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 Gigabyte, the Z77-UD4H supports memories up to 2,800 MHz.
The Gigabyte Z77X-UD4H has four memory sockets. Since DDR3 memory modules can be found in capacities up to 8 GB, you can have up to 32 GB with this motherboard if you use four 8 GB modules.
In order to enable the dual-channel mode, you must install two or four memory modules. On the Gigabyte Z77X-UD4H, the first and third memory sockets are gray, while the second and fourth are black. When installing two memory modules, use the gray sockets.