Sapphire Radeon HD 7790 Dual-X OC review

The Sapphire Radeon HD 7790 Dual-X OC is a factory-overclocked version of the AMD Radeon HD 7790, a new graphics card that plugs the gap between the £100 AMD Radeon HD 7770 and the £140 AMD Radeon HD 7850.

It’s more than a simple overclock or downclock of either of those cards though, using instead the brand new Bonaire GPU. With features that relate it closely to the hardware in upcoming next-gen consoles, the new GPU has more shader cores and texture units than the current HD 7770.

The GPU is a 28nm process with 896 stream processors. AMD’s reference core clock speed is 1GHz, but Sapphire has raised the clock speed of this version to 1.08GHz for a gentle performance boost. The card’s 1GB of GDDR5 RAM has also been overclocked to 1.6GHz from the reference 1.5GHz. Should you want to increase the memory and core clocks further, you can use the Trixx Utility that comes with the Radeon HD 7790 Dual-X OC.

The retail package includes everything you need to install the card, including to a Molex to 6-pin PCI-E power connector should your power supply not have a free PCI-E power connector. It also comes with a DVI-to-VGA adaptor, a CrossFire connector and a HDMI cable. You may not need all of these, but it’s good to have spare adaptors and everyone can make use of a spare HDMI cable. As for connections, the Radeon HD 7790 Dual-X OC has one HDMI, one DisplayPort and two DVI outputs. These outputs, together with the DVI-to-VGA adaptor, give you a great deal of flexibility when connecting your displays.

There’s all the ports you’ll need for hooking up displays

FUN PER SECOND
Initially, we tested the card with Dirt Showdown and at a resolution of 1,920×1,080 with 4x anti-aliasing and quality options set to Ultra, the card achieved a very smooth average frame rate of 55.3fps. With the resolution reduced to 1,280×720 and quality options set to High, the average frame rate leapt to 106fps. These frame rates are fantastic for a graphics card at this price, and compare well to the Radeon HD 7770-based, sub-£100 XFX R7770 Core Edition, which produced frame rates of 40fps and 97fps in those tests respectively.

In our more challenging Crysis 2 benchmark test, the Sapphire Radeon HD 7790 Dual-X OC produced an average frame rate of 24.6fps at a resolution of 1,920×1,080 with 4x anti-aliasing and quality options set to Ultra. This isn’t smooth enough for comfortable play, but dropping the quality options to Extreme produces a fairly smooth average frame rate of 36.6fps. Further reducing the quality to Very High produces an eye-pleasing average frame rate of 46.3fps.

In comparison, the XFX R7770 Core Edition produced an average frame rate of 19.6fps at a resolution of 1,920×1,080 with 4x anti-aliasing and graphics options set to Ultra, and we had to reduce graphics quality to High to get an average frame rate above 40fps. This demonstrates that the HD 7790 is the budget card to buy if you want to play the latest games at high resolutions with graphics options either set to the maximum or approaching it.

Of course, you can always sacrifice a 1080p resolution for better detail levels or smoother frame rates. At a resolution of 1,280×720 with 4x anti-aliasing and quality options set to High, the card provided an average frame rate of 106fps in Dirt Showdown. Even better, reducing the resolution to 1,280×720 in Crysis 2 but keeping the graphics options at Ultra resulted in a very smooth 48.3fps.

The single power connector means this card should work in most PCs

SEEING TRIPLE
To take advantage of the Sapphire Radeon HD 7790 Dual-X OC’s outputs, we configured three monitors in Eyefinity mode and benchmarked the card with Dirt Showdown and Crysis 2 at a resolution of 5,760×1,080.

With graphics options set to Ultra and 4x anti-aliasing, the card provided a jerky frame rate of 26fps in Dirt Showdown, but slightly reducing graphics quality to high produced a smooth average frame rate of 45.3fps, which is entirely comfortable. With the XFX R7770 Core Edition, we had to reduce the graphics quality to Low to get an average frame rate above 45fps.

Sadly, we couldn’t get a smooth average frame rate in Crysis 2, with the average frame rate being just 18.7fps with graphics quality set to High. With Eyefinity setups being the preserve of the most hardcore gamers, we can’t see the HD 7790 finding its way into their PCs.

The AMD Radeon HD 7790 fits very neatly into the bracket it was apparently designed for (though given the work that went into the GPU we find it unlikely this was its initial purpose). This Sapphire HD 7790 Dual-X OC provides excellent gaming frame rates for a price that should tempt many people. You can buy Radeon HD 7770 cards such as the XFX R7770 Core Edition for less than £100, but it’s well worth paying a little more for the extra performance of the Sapphire HD 7790 Dual-X OC. It’s out new Best Buy card.