There are reports floating around the web today that ATI is planning to refresh its RV770 (4800 series to you and me) in an effort to add additional speed to its already highly successful card line-up. This would act as a stop gap until AMD is ready to release the RV870 (5800 series).
It is already known that Nvidia is in the process of shrinking the die size in the GTX200 (to be known as the GTX 200b) series cards in an effort to reduce power and especially heat output which would enable them to bump up the speed of the GPU giving them added performance without needing to resort to designing a brand new card. The new cards are expected to be called the GTX 270 and GTX 290.
There is a slight problem with this approach, one that ATI has had previous experience with. This approach doesn't always work effectively; they have already tried overclocking top-bin (best performing) RV770 parts with little success. In an effort to help this it is reported that AMD will tweak the actual internals of the GPU itself to enable the higher clock speeds they are looking for in an effort to keep the GTX 200b at bay.
This would seem to be a priority for AMD as its ATI division has been very profitable for the company as of late, some might say even propping up the bank sheet as its Phenom CPU has enjoyed considerably less success than anticipated before launch.
The 4800 series currently holds both the price/performance crown (4870) and the out-right performance crown (4870 X2) forcing Nvidia to radically drop the pricing of its GTX200 series products, if the GTX200b signalled a serious comeback it could force AMD to drop its prices, and with the current debt mountain that AMD currently has it could spell disaster to any idea of a recovery for AMD's bank balance.