3870 X2

For well over a year Nvidia has remained at the top of the PC graphics market, holding the performance crown so comfortably they never looked as they might lose it.

Looking back in time we discover that the only threat from competition in recent times came from the Radeon HD 2900XT, which was never meant to defeat the GeForce 8800 GTX anyway. Then late last year we saw the arrival of the ATI Radeon HD 3870, though again this product was not in contention for the performance crown, although it served well its purpose of creating more value in the mainstream price points.

As we entered 2008, Nvidia remained and still is almost tight lipped about a true next-generation product that could push the performance envelope further. At the same time we were expecting AMD/ATI to hold its promise about a dual-GPU solution based on the Radeon HD 3800 that unlike conventional multi-GPU technology, would not require a Crossfire-compatible platform to work, and would become a real contender in the high-end graphics market.

The Radeon HD 3870 X2 puts two GPUs in a single card.

You won’t be surprised to learn that the specification of the X2 bears an uncanny resemblance to a pair of HD 3870s while the appearance is very much like a 3870 with an extra couple of inches tacked on the length. While Sapphire’s first take on the X2 is a reference design, Asus has done something that is most unusual by producing an X2 with four DVI ports.

The X2's GPUs are made using the same 55nm production process as the HD 3870, and they support DirectX 10.1 and Shader Model 4.1, and have 320 Stream Processors in each chip. That’s 640 Stream Processors in total with a transistor count that has climbed past 1.3 billion. Each GPU has 512MB of GDDR 3 memory to itself, connected to its own 256-bit controller, so there’s 1GB in total.

The card is longer than a regular HD 3870 board, but it looks very similar and has the same beefy heatsink along the full length of the card, with a dust-buster fan at the far end that draws cooling air from inside your PC case. The air is blown through the heatsink and exhausts through the vented bracket to the outside world.

The core speed of the X2 has been increased from the HD 3870's 775MHz to 825MHz, while the memory speed has decreased from 2250MHz to 1800MHz. The memory controller supports both GDDR 3 and GDDR 4 so it would be no surprise if a graphics card manufacturer was to come up with an X2 with 2GB of fast memory. Whether it would make any sense is a completely different question.