In our first article on the HD 6870, our discussions revolved around its performance in games. The card did very good in some titles, while in some others, such as Metro 2033, we’re still not quite satisfied by the amount of frames per second produced by this card. It would, therefore, be really nice if we could multiply its processing power.
One logical way to improve performance significantly is by adding another HD 6870 and run the pair in multi-graphics configuration, which is relatively easy to do since the card has native CrossfireX support. How much additional performance can you expect from this multi-card setup anyway? We’ll get to that, but first, let’s examine the technical specs first.
|AMD Radeon HD 6870||AMD Radeon HD 6850|
|Codename||Barts XT||Barts Pro|
|Fabrication Process||40 nm||40 nm|
|Transistors||1.7 Billion||1.7 Billion|
|Die Size||225 mm2||225 mm2|
|Core Clock||900 MHz||775 MHz|
|Memory Size||1024 MB||1024 MB|
|Memory Clock (effective)||4200 MHz||4000 MHz|
|Power Connectors||2x 6-pin||6-pin|
|Min Recommended Power Supply||500 Watt||500 Watt|
|Bus Support||PCIe 2.1 x16||PCIe 2.1 x16|
You need at least two Radeon cards for CrossfireX setup. While not required, it would be better if both cards are identical. You will also need a motherboard with two PCIe x16 slots. Crossfire support is available on Intel motherboards based on the series 5 and 4 chipset families. It is also supported by motherboards based on more recent AMD chipsets (series 8 and 7).
Connect the two Radeons using a CrossfireX Bridge placed on top of the cards.
You will also need at least a 600 Watt power supply with four, 6-pin PCIe connectors.
When both cards have been properly positioned in their slots, it’s time to install the driver software. CrossfireX will be detected and activated automatically.