Great run Mat.. How is the temperature? If good try 1.6V..

The GPU temp remain under 50°, but I think the problem is the standard VRM Circuits of this NON-Reference HD4850 that is near is limit. The VRM became very hot and I've already placed heatsinks to Inductors and to Mosfets.

By raising the extra 0,050v overvolt I only gain 10MHz!