MSI Computer Corp. ATI Radeon HD7770 1020 MHz 1GB DDR5 PCI-Express 3.0 x16 Graphics Cards R7770-2PMD1GD5/OC Engine Clock: 1020 MHz Video Memory: 1GB DDR5 Memory Clock: 4500 MHz Memory Interface: 128-bit Bus: PCI-Express 3.0 x16