The rumour claims GTX 680 will offer similar performance to AMD's Radeon HD 7970. Clock speed is 780 MHz - no higher than GTX 580 - while it sports 2GB memory. While this suggests a 512-bit or 256-bit memory bus, NVIDIA has in the past mated 1GB to 192-bit with GTX 550 Ti, so it is possible GTX 680 has a 384-bit memory interface. Little else is revealed about the mysterious GTX 680.
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