A Closer Look

AMD's reference design cooler is powerful, big and heavy. The total weight of the card is 1060 grams (GTX 280: 920g, HD 4870 790g). Please make sure you properly screw down any large VGA card before moving your case to a LAN party.
As you can see there are two copper blocks making contact with the GPUs, while the memory chips and other circuitry is cooled with thermal pads. The memory chips on the back of the card are cooled by a metal plate (yes it's metal, even though it feels like plastic).


Two of these cards (or 4870 X2 + 1x/2x 4870) can be combined into a CrossFireX rig with even more graphics power.


Just like on the HD 3870 X2, the power connectors are angled downward which helps in smaller cases. Please note that you need to connect both 6-pin and 8-pin PCI-E power connectors for the card to run. Two 6-pins won't work; you must use an 8-pin power connector for the 8-pin plug.


Mmmm, nice. These are the first GDDR5 memory chips from Hynix that I see. On the HD 4870, chips from Qimonda are used. The model number of the chips on the HD 4870 X2 is H5GQ1H24MJR T0C, they are specced for up to 4.0 Gbps (= 1000 MHz real clock). In total you will find 16 of these memory chips on the 4870 X2, eight per GPU.


The PLX Technology PEX 8647 is a PCIe Gen2, 5.0GT/s 48-lane, 3-port PCIe Switch (marketing spec sheet here).
While the bridge chip on the HD 3870 X2 supported only PCI-E 1.1 transfers, this one has full support for PCI-E 2.0, and also offers new features like Dual Cast and Read Pacing (see the spec sheet for explanations).


Each of the two RV770 graphics processors used on the HD 4870 X2 is the same as on any other Radeon HD 4850 and HD 4870.