As anyone remotely in tune with the tech sector can attest, the rivalry in the PC graphics card market between AMD / ATI and NVIDIA is as intense as ever. It used to be that one of the two companies would release a new product, only to have the other release a competing offering a few weeks, or maybe a few months later. But even in these gloomy economic times, AMD and NVIDIA continue to fight on and today both graphics giants are releasing new graphics cards aimed squarely at one another. Not a few weeks apart, but simultaneously on the very same day. Don't believe us? We've got some NVIDIA GeForce GTX 275 coverage too.

AMD is rolling out the ATI Radeon HD 4890 today, technically a new graphics card, but one that borrows heavily from the previous generation. The Radeon HD 4890 is based on an updated variant of the popular RV770 GPU which powers Radeon HD 4850 and 4870 cards, dubbed the RV790. We've got some technical details regarding the RV790 GPU below and have more particulars regarding the actual cards and performance on the pages ahead. Read on to see what AMD has in store with the brand new Radeon HD 4890...