The ATI 3870 X2
The 3870 X2 is a huge card, similar in size to the 8800 Ultra. Attached to the front is a dual slot cooler with fan similar to the one used on the 3870. Along the top edge of the PCB are two power connectors, an eight pin and a six pin. On the back of the card we find a black heatsink which covers, and cools, various components including eight of the cards sixteen memory chips. Display outputs on the X2 come in the form of two dual-link DVIs which support 2560x1600 as well as HDMI conversion and 5.1 audio. The TV-out on this card supports s-video, composite and component which matches other high end Radeons. Like the other recently released ATI cards this model is fully HDCP compliant and features High Definition video acceleration. Along the top edge of the PCB we can see a single CrossFire connector which would allow us to connect and use two X2’s together provided a suitable driver (and motherboard) was also used. Finally along the bottom of the card is the PCI-Express 2.0 connector which is PCI-Express 1.x compatible.
After removing the cooler we can see that various components receive cooling in addition to the core, the more notable items being the two Pulse 1312’s. Also immediately noticeable is that each core on the 3870 is cooled by a different material, one by copper the other by aluminium.
Looking more closely at the card we see that it uses the R680 core, the same used on the standard 3870 and this means each GPU using a 256Bit bus to connect to its 512mb of DDR3. There are sixteen ROPs per core and 320 unified shaders. DirectX 10.1 and therefore Shader Model 4.1 are supported and (as with the standard 3870) the various power saving features are also present.
Connecting the two GPUs is a PLX Technology PCI-Express switch, model PEX8547-AA25BC G. This chip features forty-eight PCI-Express lanes, is 1.1 specification compatible and is designed primarily for use on graphics applications. The cores on the 3870 X2 are clocked at 825MHz in 3D tasks and run at 300MHz in 2D mode. The memory is Samsung branded, clocked at 900MHz and rated to 1000MHz (K4J52324QE-BJ1A) so there is, in theory, considerable room for overclocking.
