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 1,920x1,080 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 1,280x720 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 1,920x1,080 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.