AMD Radeon HD 6790 review

The AMD Radeon HD 6870 and AMD Radeon HD 6850, released late last year, both gained Best Buy awards, but we were still left waiting for the follow-up to the cheaper HD 5770 – our favourite graphics card of the previous generation.

This has now arrived, in the shape of the HD 6790. According to AMD, this slots in between the HD 5770 and the HD 6850 in AMD’s range and, at £116 for the Sapphire version of the card (below), its pricing is right between the £100 HD 5770 and the £140 HD 6850.

The new card’s specification isn’t spectacular. It has 800 stream processors, which is the same number of units as the HD 5770 but 160 fewer than the HD 6850. 1GB of GDDR5 RAM comes fitted, just like on the HD 6850, and this runs at 1.05GHz – 150MHz slower than the HD 5770’s RAM. The HD 6790’s 256-bit memory bus does eliminate the HD 5770’s 128-bit bottleneck, though. The card’s core clock speed is 840MHz – similar to the HD 5770’s 850MHz.

The ‘mid-range’ HD 6790 can draw 150W, and has two PCI-E power connectors.

We were surprised by the HD 6790’s design, as it looks like a much more powerful card – it’s 262mm long, which is longer than the HD 6850 and huge for a mid-range card, plus it has two six-pin power connectors. Luckily, the HD 6790’s performance in our benchmarks came close to matching its looks. In Crysis at 1,680×1,050 with High detail and 4x anti-aliasing enabled, the card gave us a smooth 41.8fps – a big improvement on the HD 5770’s 33.6fps, and not far off the HD 6850’s 48.7fps. Pushing the resolution up to 1,920×1,080 narrowed the gap, with the HD 6790 managing 37.2fps compared to the more expensive HD 6850’s 42.6fps.

In our challenging DirectX 11 Stalker: Call of Pripyat benchmark, which we run at 1,920×1,080 with High detail and 4x anti-aliasing, we saw 30.7fps from the HD 6790, compared to 33.3fps from the HD 6850. Overall, the performance difference between the HD 6790 and the HD 6850 is between 8% and 12%, compared to about a 16% price difference between the cards. This shows that AMD has got its sums about right – both cards are equally good value, so which you buy depends on how much you want to spend.

You can squeeze some useful extra power from the card by overclocking it.

We did almost manage to match the HD 6850’s performance by overclocking the HD 6790 to 940MHz core and 1,150MHz memory speeds, using the Catalyst Control Center’s AMD Overdrive function. If you’re willing to do this you may have a bargain on your hands. The one thing AMD has managed to do is neutralise the threat from Nvidia, with its mid-range GeForce GTX 550 Ti. This costs around £112, but it’s nowhere near as fast as the HD 6790.

The HD 6790 is a very capable card, providing plenty of performance at a reasonable price. It fits seamlessly into the range, just beneath the HD 6850. Whether you buy this or the HD 6850 depends very much on pricing when you buy. At launch this card looks a little expensive, but if prices drop by even £10, it will find a very handy niche of its own.