ASUS has introduced two Radeon HD 4770 graphics cards today, the EA4770 and the overclocked EAH4770 TOP. The standard model has a 750MHz core and 512MB GDDR5 clocked at 3200MHz, while the TOP edition has a 800MHz core and 3400MHz memory.
This is a 50MHz overclock for both the GPU and memory, and Asus is currently the only partner that has an overclocked card, at least as far as we know. Another interesting thing is that Asus included its Voltage Tweak Technology with the Asus EAH4770 TOP card which raises the GPU voltage from 0.95V to 1.2V. This voltage boost is enough to raise GPU and memory frequencies from 800MHz to 971MHz and from 3400MHz to 4600MHz.