So that makes the new 4870 card an 'update' rather than new technology. AMD's next high-end graphics card is as you guys all heard, built on ASIC RV790. It's however still based on a 55 nm manufacturing process.

Sources tell German website Hardware-Infos that the new GPU perform better and run at higher clock-speeds than RV770 (4870). The ASIC is absed of an improved 55 nm manufacturing process.

RV790 engineering-samples undergoing testing are known to be coming in two flavours according to the source: a base model and an overclocked model. The base model comes with the same exact clock speeds as the RV770XT: 750/900 MHz (core/memory), while the overclocked model is known to come with clock speeds of 850/975 MHz (core/memory). To achieve that 100 MHz increment in core frequency, the voltage is known to be stepped-up from 1.24 to 1.30 V.

Products based on this GPU are known to surface by April [via TPU and Hardware-Infos]