Upon initial inspection, the Radeon HD 4870 X2 looks much like the Radeon HD 3870 X2, just with different PCB coloring. The card features a dark, black PCB with an industrial looking image of bolts and the Radeon logo emblazoned on the fan shroud. Flip the card over, and as you probably expect, the complexity of the design shows through.
We acquired cards from HIS and Palit for this article, both of which are pictured here. In terms of their features and specifications, the Palit and HIS Radeon HD 48070 X2 cards don't differ from ATI's reference design, save for a couple of decals and their accessory bundles.
As we’ve already mentioned, the Radeon HD 4870 X2 is powered by a pair of 750MHz RV770 GPUs, the same chips used on the Radeon HD 4870 and 4850. The two GPUs are linked together on the PCB through a PCI Express 2.0 fan-out switch from PLX. That switch takes the 16 PCI express lanes coming from the PEG slot and distributes them to both of the GPUs.
Like the Radeon HD 3870 X2, the new 4870 X2 has only a single CrossFire edge connector along the top of its PCB. It has only one because the other connection is already utilized on the PCB as an interconnect between the on-board GPUs.
Each of the GPUs on the Radeon HD 4870 X2 has its own 1GBMB frame buffer, for a total of 2GB of on-board memory. As you can see, the entire assembly is quite large and results in a 10.5” PCB – a little longer than a standard ATX motherboard. The cooler used on the card is much like previous offerings, but there are some noteworthy elements to the design. Each of the GPUs gets its own heatsink, as do the surrounding switch and RAM. The squirrel-cage type fan draws air in through a hole at the rear of the card, blows air across the heatsinks, and expels it from the system through vents in the mounting plate.
Like the other members of the Radeon HD 4800 series, the ATI Radeon HD 4870 X2 has a pair of dual-link DVI outputs, and an HD video output. One of the DVI outputs can be converted to an HDMI output with audio using an included adapter.
The Palit samples we received did not come in full retail trim, so we can't comment on the included bundle at this time. The HIS card, however, was retail-ready and included a drive CD and manuals, a CrossFire bridge connector, a DVI-to-VGA adapter, a DVI-to-HDMI adapter, an S-Video to composite adapter, an HD component output dongle, a Molex-to-PCI Express power adapter and an HIS case badge.