XFX HD 7970 Black Edition Double Dissipation 3 GB Reviewccokeman -
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While the reference card featured an all-new shroud design with the familiar squirrel cage fan and tweaks to improve Crossfire Cooling performance, the XFX Black Edition Double Dissipation HD 7970 features a radical departure. Slightly longer than the 10.5 inch reference card at 10.8 inches long, the Black Edition fits in just about the same footprint and should not provide any challenges installing it into most chassis. The front view shows the Double Dissipation cooling fans and Ghost technology shrouding over the Hydrocell vapor chamber-based heat sink. The rear of the card is much like that of the reference card, without a backing plate or any memory modules taking up residence on the back of the black PCB. Across the top of the card is a red accent strip that displays the name of the card and cooling technology to provide visibility through the windows of many gaming chassis.
Much like the reference card, the venting on the Black Edition has been opened up to reduce the acoustics and improve airflow through the rear of your case. On top of that, XFX has their own rear bracket that is supposed to improve airflow even further – the connectivity has been paired down to a single DL DVI, 2 Mini DisplayPort 1.2 connections, and an HDMI port that supports the HDMI 1.4a standard. DisplayPort 1.2 supports the use of an MST hub or daisy-chaining Displayport monitors into an Eyefinity configuration of up to six monitors. With Eyefinity 2.0, there is also added functionality of independent audio streams for each video stream, so that the audio streams follow the video to each specific monitor. The back end of the card is void of any detail and is not vented, except on the bottom and top of the shroud.
The XFX Black Edition HD 7970 supports CrossfireX in configurations that use up to 4 cards by way of the dual Crossfire Bridge connections on the spine of the card. Behind the bridge connections is the dual BIOS switch that can be used to flash a custom BIOS or recover from a bad BIOS flash. Power connectivity comes by way of a single 8-pin and a single 6-pin PCIe power connection to supply the 250 watt maximum board power requirements. It looks like the original idea was to use two 8-pin power connections, as the connection points are on the board but not utilized – much like the reference card.
Under the shroud is a large vapor chamber-based cooling solution that cools the Tahiti core, while the aluminum bracket cools the 3 GB of GDDR5 memory and power circuitry of the card. A pair of PWM-controlled 90 mm fans is used to draw the heat from the board components, blowing down through the heat sink assembly and out the top, bottom, and mounting bracket, which keeps all the board components cool.
The basis for the HD 7970 is AMD's all-new Tahiti 28 nm architecture. Not only is there a process shrink, but an increase in transistor count to 4.31 billion, stream processor count to 2048, and texture units to 128, while the ROP's stay at 32. GDDR5 memory is used with an increase in capacity to 3 GB on a 384-bit bus. In this case, XFX has boosted the clock speeds on the GCN core from 925 MHz to 1000MHz and boosted the speeds on the 3 GB of GDDR5 so that it runs at 1425 MHz. 2 Hynix GDDR5 modules with part number H5GQ2H24MFR-R0C are used to make up the 3 GB frame buffer and are rated to run at 1500 MHz. Software-based voltage control is possible with the use of the CHIL voltage controller.
With custom cooling and increased clock speed, the XFX HD Black Edition Double Dissipation HD 7970 should offer up a nice increase in performance at stock speeds as well as improved potential as the voltage is ramped up to increase the clock speeds further.