Although AMD took the hardware community by surprise with the performance of the RV770, and NVIDIA immediately turned around and slashed the prices on its own models, determined to win this round of the ongoing graphics card war. AMD is not out just to make waves with the gamers looking for value. It also wants to reclaim a crown it lost a long time ago to NVIDIA's last two generations of large, monolithic programmable graphics architectures. As a means to that end, the company is putting a pair of its most impressive GPU's on a single PCB and calling it the Radeon HD 4870 X2. Does the new board have the muscle to take on NVIDIA's GeForce GTX 280, the single fastest card? - Tom's Hardware

AMD Radeon HD 4870 X2 2GB Graphics Style Review

Contrary to what its code name might otherwise suggest, the R700 actually centers on a design sporting two RV770 GPU's. The two GPU's are positioned together on the same PCB, though you won't see them since a heatsink with fan combination covers the entire board. In appearance, the Radeon HD 4870 X2 remains similar to the Radeon HD 3870 X2 card. Not surprisingly, the card itself is quite long and it sports a large blower that exhausts through the back of the board and is neighbored by two dual link DVI outputs. The board requires one 6-pin and another 8-pin PCI Express power connector.

As with the Radeon HD 3870 X2 video card, a PCI Express bridge manages the communications between the two GPU's and the chipset. Once the final display outputs is calculated, each GPU sends them to another chip that assembles the result and sends them to the monitor. When we tested the Radeon HD 3870 X2, we found that the biggest impact on performance was attributable to the board's memory capacity, since memory on a bi-GPU card has to be divided in two. And in order to assure adequate performance, you often have to increase the quantity of memory, which is what AMD does with the Radeon HD 4870 X2 graphics card.

Reasonably silent at rest, the Radeon HD 4870 X2 turns out to be quite noisy when in use, right from the time that its fan starts spinning up. On the other hand, we also want to note that while the GeForce GTX 280 is pretty noisy at rest, it is much more bearable than it used to be under load. Although the Catalyst control center permits us to directly augment the frequencies of the GPU and memory it also limits their values like 800MHz for the GPU and 4GHz for the memory. It is possible to override this via third party overclocking software, and to unlock the Radeon HD 4870 X2 video card for some serious overclocking.

The Radeon HD 4870 X2 manages to achieve its objective, namely to be the best performing card you can buy. It has been a long time coming, and other Radeons have had the same goal but have not been able to attain the same results. It must be said that the design of the Radeon HD 4870 X2 takes into account the mistakes made with the Radeon HD 3870 X2. The memory capacity has been increased, so that now there is 1GB of usable memory per GPU. Considering the size and price of NVIDIA's GT200 chipset, and it is prohibited from any sort of retaliation based on the same bi-GPU solution and technology.

In short, the Radeon HD 4870 X2 card is the newest and fastest 3D card of the moment, about 25% better on average than the GeForce GTX 280 and up to fifty percent at the highest resolutions. There's also a side port connection between the GPU's reserved for future use when the PCI Express 2.0 pathway might become saturated. If you're hoping for something in the near future with lower energy consumption, less noise, or a lower price, we'd recommend you not hold your breath.