synchronous graphics RAM (SGRAM)
Synchronous Graphics RAM (SGRAM) is a fast graphics memory with a synchronous interface. The access times are between 8 ns and 15 ns, the clock rate is 166 MHz. SGRAMs work as clock-synchronous DRAMs and, unlike VRAMs, have one port.
SGRAMs have 32 data lines and are characterized by special write commands: Mask-Write and Block-Write. Mask write is masked write that allows selected data to be changed in a single operation rather than as a sequence of reads, updates, and writes. Block write, or block-by-block writing, allows data to be accessed and modified on a block-by-block basis, significantly reducing the number of writes and reads, which helps increase efficiency.