VR-Zone reports AMD to launch Radeon HD 4890 (standard edition) in April. The RV790XT A11 sample has a clockspeed of 850Mhz and a operating voltage of 1.3V. It will likely be paired with 975Mhz GDDR5 memory. By comparision, the current Radeon HD4870 (RV770) model runs at 750MHz core clock and 900MHz memory clock. There will be 2 versions of the Radeon HD4890 - a standard edition and a OC edition. The standard edition will launch in mid April, with the OC Edition following shortly after by end of April. The Radeon HD 4890 OC Edition has 1GB of GDDR5 memory onboard and is expected to perform 25-30% faster than HD 4870. It is expected to be priced at USD299 at launch.