Having presented two Tahiti-based models already, one factory-overclocked and with an aftermarket cooler, suffixed “OC”, and another based on the referent solution, Sapphire has decided to surprise us with its best graphics card to contain the Tahiti GPU - Radeon HD 7970 Dual-X. We’ve recently had the chance to test two other expensive HD 7970 cards, intended for enthusiasts, both being excellent, non-compromising choices. However, their availability is questionable, and the same goes for their price, since the additional 5% you can squeeze out on air cooling isn’t worth the price difference (unless, of course, you’re going for water or even liquid nitrogen as coolant). For those who like to overclock and overvolt, but also stick to the capabilities of air cooling, Sapphire has an excellent solution which offers a lot more than the referent product for a very small increase in price.

The typically Sapphire simple-design box contains a large number of extras, which is a practice employed by Sapphire for a while now. Honestly, nearly all other manufacturers can look up to them in this regard, as the equipment they include is unmatched. As always, there are the manual, driver disc and software overclocking tool. The plethora of adapters covers all or nearly all imaginable scenarios, including DVI-to-VGA, miniDP-to-DP, DP-to-DVI and miniDP-to-DVI, all available as extension cords; furthermore, there are also molex converters for those who don’t have a 6- or 8-pin connector on their PSU. The CrossFireX cable makes an appearance too, and the same goes for the 1.8-metre HDMI cable. Finally, the buyer also gets the gold membership card to Sapphire Select, Sapphire’s privileged customers’ club, offering free games and other niceties that can be found on the official website.

Of course, all this talk about the bundle wouldn’t carry a lot of weight without the graphics card itself. Even the first glance at it reveals its similarity to the OC version, but with a few very important differences. Firstly, the large dual-slot cooler has a not-too-high-quality plastic shield, which is one of the rare things we have to reproach to HD 7970 Dual-X, but also many other Sapphire graphics cards as of late. Although we have nothing against the material itself, despite the fact that most other manufacturers have switched to aluminum for this purpose, we are bothered by the design and final polish (or lack thereof), both of which make the card look cheap, which shouldn’t be possible after you’ve cashed out at least 450€ for a graphics card. Two fans with a diameter of 9 cm and a large number of blades look very good; however, both in terms of airflow and noise, and our later testing showed that the initial gut feeling was right. The cooling body is made of aluminum, intersected by five heat pipes, two of which are 8 mm and three are 6 mm thick. This cooler doesn’t belong to the Vapor-X series, which means that the base is made of copper. The PCB itself sticks to the referent design, which implies a 7-phase power unit and shielded coils. We were happy to see memory chips and the power unit covered by passive coolers, in the form of black aluminum profiles, aided to a certain extent by airflow generated by the fans. The central section of the card is occupied by the Tahiti GPU in its full version. It’s made in TSMC’s quarters and is the strongest AMD currently has to offer with its GCN architecture. The chip has full hardware support for DirectX 11.1, ShaderModel 5.0 and OpenGL 4.1, with all the new technologies inherent to the Southern Islands family, namely Eyefinity 2.0, ZeroCore etc. It has 2048 stream processors, 128 texture and 32 ROP units, all of which are pretty impressive numbers. With a declared consumption of around 250 W, Radeon HD 7970 looks less optimized than NVIDIA’s Kepler for now, but the fact that performance has been increased compared to Cayman while retaining the same TDP still makes Tahiti a very efficient chip. The GPU is surrounded by twelve GDDR5 memory chips, forming a 384-bit bus. The total memory capacity is 3 GB, and although this has proven to be more than enough for any regular use, if you’re going for an Eyefinity configuration with three or more monitors, 3 GB of video memory can come in very handy. As for connectors, you’ll need an 8-pin and a 6-pin connector to power the card. CrossFireX is possible with up to two additional cards, via the two appropriate connectors. Unlike the recently presented models by ASUS and MSI, this card doesn’t have the extra outputs, but two DVIs, an HDMI and a DisplayPort, which is more than enough for any user who doesn’t plan on using six video outputs at once, or in other words, almost everyone.

 As for the “Dual-X” bit of the card’s name, it refers to the two fans, but also the dual-BIOS the card has. Fair enough, every Radeon HD 7970 has two BIOS, even the referent versions. However, Sapphire used this capability very well, by using the first BIOS to set the card to somewhat lower frequencies and a rather silent profile for automatic fan control. The second BIOS speeds up the card to 1000 MHz for the GPU and 1450 MHz (5.8 GHz) for the memory, as well as enabling the fan to work much more aggressively, so that users can get the most out of their card’s overclocking potential. Since the card has the CHiL chip installed, the GPU and memory voltages can be manually controlled, which is yet another pointer at the sportive spirit of this model.

Laudable performance

 This card packs not only excellent performance, but also very low noise levels, regardless of which BIOS you’re using. Therefore, if you’re lucky enough to be able to afford a card like this, turn the switch to the second position immediately and enjoy the additional performance boost, as the increase in noise is hardly detectable in usual conditions. Overclock is another bright spot in this model’s record, as we were able to reach 1225 MHz for the GPU and an effective 6240 MHz for the memory, reaching a memory bandwidth of an entire 300 GB/s! The effective gains are at around 15%, which is definitely commendable, despite the limitations imposed by the full HD resolution, the latest limiting factor for the latest-gen “monsters”, Tahiti and Kepler alike. Either way, Sapphire has done an excellent job, and the only problem may come in the form of GeForce GTX 680, a huge threat to AMD if they don’t escalate the price war soon. Truth be told, the availability of the strongest GeForce is still unimpressive to say the least, but the situation is poised to change, and we’re awaiting AMD’s reaction eagerly.