Sapphire HD 7870 GHz Edition (OverClock Edition) is a dual slot graphics card that’s 25.4cm long. Sapphire used a blue PCB that’s typical of Sapphire but is still based on the reference design. The PCB itself is 24cm long but the cooler is slightly longer as you can see from the picture below.
It is interesting to see heatpipes on the bottom rather than at the top of the card. We presume that this improved dissipation since the aluminum heatsink goes almost to the top of the card, where there’s more fresh air. Whether heatpipes go downward or upward is irrelevant as long as the cooler does its job as it should. The fans are 8.5cm in diameter and our testing revealed that they are quiet. Both fans are connected to a single 4-pin power connector and RPM regulation is automatic. Naturally, you can use any tool such as CCC Overdrive to do manual control.
Lately we’ve seen increased use of 8mm pipes but 6mm ones are still considered standard for graphics. However, Sapphire combines thinner 6mm pipes in the middle of the heatsink with thicker 8mm pipes that must transfer heat to far edges of the heatsink.
The way heatpipes touch the heatsink is quite interesting. Heatpipes usually pass through heatsinks where they cannot be seen, but Dual-X’s heatpipes don’t fully enter the heatsink so we can see an entire side of the pipe. Contact pipes and aluminum fins on the heatsink are very tough and it seems as if the heatsink is better than the standard ones.
Quality cooling wouldn’t be complete without memory cooling. With that in mind, Dual-X cooler is equipped with special heatspreader that is curved on top of the card for better dissipation.
HD 7870 card features eight GDDR5 memory modules, each packing 256MB and totaling at 2048 on the card. A single 64-bit memory controller holds two memory chips, which means that HD 7870 has a 256-bit memory interface.
Some AMD partners decided on including an additional DVI out on HD 7870 cards but Sapphire stuck to the reference design with one dual-link DVI, two mini-DisplayPorts and a single standard HDMI out. However, Sapphire bundles a bunch of converters with the card – you get HDMI-to-DVI dongle, 1.8 meter long HDMI cable, mini-DisplayPort-to-DisplayPort dongle and one DVI-to-VGA dongle.
AMD’s HD 7000 series comes with support for multiple independent audio streams. HDMI 3D offers support for Deep Color, 7.1 High Bitrate Audio and 3D Stereoscopic. Doubling the effective bandwidth of previous DisplayPort implementations, DisplayPort 1.2 now includes support for Multi-Stream, allowing you to drive up to four separate monitors from a single DisplayPort 1.2 connector (requires DP1.2 monitors or Multi-Stream compatible hub), Stereoscopic 3D monitor support and adds support for high quality, lossless, 7.1 channel audio formats.
HD 7870 has a single Crossfire connector, meaning that an additional HD 7870 will help boost performance.
AMD’s reference card can draw up to 175W, but the two 6-pin connectors ensure that the card has 225W at its disposal. Although slightly overclocked, Sapphire’s card shouldn’t draw much more than the reference version.