PowerColor ATI Radeon HD7770 1000 MHz 1GB DDR5 PCI-Express 3.0 x16 Graphics Cards AX7770 1GBD5-2DH Engine Clock: 1000 MHz Video Memory: 1GB DDR5 Memory Clock: 4x 1125MHz (4.5 Gbps) Memory Interface: 128-bit Bus: PCI-Express 3.0 x16