When the rumor mill started grinding on about the "RV790," a future high-end AMD graphics processor, one might have assumed that chip would be based on 40nm process technology. After all, word is that a 40nm RV740 GPU will hit mainstream graphics cards in May. But no dice. Expreview reports that AMD will in fact rely on an older 55nm process to get the RV790 manufactured.
Quoting an anonymous source, the Chinese site says the RV790 will essentially be a "super-overclocked" version of the current RV770. AMD will clock it at 950MHz (200MHz faster than the RV770 in the Radeon HD 4870) with no changes to the stream processor count or the matching GDDR5 memory. Expreview claims the GPU will launch in a new Radeon HD 4970. (Previous rumors mentioned a 4890 model number, for what it's worth.)
If this rumor checks out, then AMD may simply aim to compete with Nvidia's GeForce GTX 285. That new graphics card wears the single-GPU performance crown, but it also carries a $100 premium over the GeForce GTX 260 "Reloaded" and Radeon HD 4870 1GB.