German hardware site Hartware got their hands on some information regarding AMD's Radeon HD 4000 series. Keep in mind that they weren't able to verify this information, it's possible that someone just pulled all this information out of his ass.
All these cards are made on a 55nm process and support DirectX 10.1. Some of the high-end cards will get GDDR5 memory and all cards will feature Power Play+ so the power consumption in idle will remain below 20W. The first Radeon HD 4000 series cards are expected in June.