Sapphire Radeon HD4850 X2 graphics card

At the time of writing, Sapphire’s Radeon HD4850 X2 is the first and only example of the dual-GPU version of AMD’s mainstream HD4850 graphics card.

The HD4850 X2’s two RV770 cores are connected internally by a Crossfire bridge and each has 1GB of GDDR3 memory (a dual-512MB model will be launched shortly) clocked at 993MHz (in effect, 1,986MHz with two processors) running via a 256-bit interface.

Core and shader clock speeds are the same as the single-cored version: 625MHz for both. Just like its bigger brother, the HD4870 X2, it’s a big card that needs a fair amount of power and, to that end, it comes with eight-pin and six-pin power connectors.

Unlike the HD4870 X2, the HD4850 X2 uses two cooling fans in a double-height cooler, which keeps the card very cool. However, the review device was a very early board with drivers that didn’t have any fan control built in, so the fans were spinning at high speed all the time, making it noisy; retail boards should have this problem ironed out. On the back of the card there is a passive heatsink to keep the power regulators cool.

While the Radeon HD4850 X2 may be aimed at gamers, one of its features will appeal to workstation users: the four dual-link DVI ports on the expansion panel, allowing for multi-monitor setups. While all four outputs are HDCP-compliant and can be used with an HDMI adapter, only two of the four will support audio output, including native 7.1 surround sound.

HDMI, VGA and Crossfire adapters are included, with both six-pin and eight-pin PCI-E-to-Molex power connectors – handy if your power supply isn’t a current one. The software bundle includes Futuremark’s 3Dmark06 benchmarking tool.