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Radeon HD 4890 X2 a Reality On The Basis of Performance Against Competitor
AMD is attempting to revive its competitiveness that took a beating with NVIDIA's introduction of 55 nm G200b-based graphics accelerators. The method AMD seems to be adopting is by giving its existing flagship GPU, the RV770, a series of design improvements that facilitate higher clock-speeds, in turn, better performance on offer.

A lot has been said about RV790 till date, with each commentator coming up with a new version of the story. It has been more or less established that the RV790 will be a improvement over the RV770, though not a revolutionary one. Fresh information gathered by PC Games Hardware places a realistic estimate on up to where RV790 is going to push the performance envelope for AMD.

It is suggested that RV790 will revive direct competition with NVIDIA's GeForce GTX 260, post the company's remodeling of the SKU by enabling 216 stream processors against 192 on its original specs. With the single-GPU flagship accelerator based on the RV790: Radeon HD 4890 competing with GeForce GTX 260 (216 SP), one would wonder if the company would work on a dual-GPU accelerator. NVIDIA's GeForce GTX 295 emerged as the fastest dual-GPU accelerator, outperforming ATI Radeon HD 4870 X2, although it achieved that by using two G200b cores with all their 240 stream processors enabled. This leaves a tough task for AMD to design a card that outperforms GTX 295, considering the higher clock-speeds the RV790 comes with, ideally, only pushes the performance of the single-GPU card by 8~20 per cent. While there are no technical challenges the company faces in designing a dual-RV790 accelerator, it will do so only if it is able to outperform the GeForce GTX 295. AMD's add-in board partners (AIBs), most probably will be left to design their own dual-RV790 cards, much in the same way AMD left it to them, to design the Radeon HD 4850 X2.

From AMD's end, it seems like the company is treating the "X2" moniker as an object of prestige, that it would not want to tarnish by releasing something that falls behind its competitor in terms of performance. The HD 3870 X2 outperformed its then competitor, the GeForce 8800 GTX, followed by HD 4870 X2 outperforming GeForce GTX 280.

Source: PC Games Hardware