AMD Radeon HD 6870 review

Our initial reaction to the launch of the new 6000-series Radeon graphics cards was one of mild disappointment. Probably not the reaction AMD was looking for, especially having finally retired the ATI name in favour of using its own three letter moniker.

Radeon 5000-series cards have dominated our awards in recent years, and we were hoping for a big leap forward in performance, matched undoubtedly by a serious price hike. Instead, with the new HD 6870 and HD 6850, AMD has chosen to refine its current architecture, and release a pair of good value, power efficient cards.

This HD 6870, confusingly, lines up against the HD 5850 in terms of pricing. The new card is a good example of getting more out of less. The die size of the GPU has been reduced by around a quarter, with a similar drop in the total number of transistors. There are less stream processors too, 1,120 rather than 1,440. Some clever architectural tweaks have improved performance, particularly a redesign of the front end, which handles sending tasks to the stream processors. The memory bus remains at 256-bit, so there’s no bottleneck there, and the 1GB of GDDR5 memory runs at a respectable 1050MHz.

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The real gains have been made by an increase clock speed. It has shot up from 725MHz on the HD 5850 to 900MHz on the HD 6870. This is largely possible thanks to the smaller GPU, which stays cooler. The performance gains are obvious. With it scoring 7fps more in our Crysis test than the HD 5850. At 1,920×1,080 with 4x anti-aliasing it managed a smooth 46.6fps – finally an affordable card that’s untroubled by this resource-hog of a game.

The card is optimised for DX11, with its range of fancy new graphical effects. A new tessellation engine, which automatically scales the amount of detail required in any 3D object depending how far it is from the camera, is the key element here. It works too, with the HD 6870 scoring 10fps more than its predecessor in our Stalker test.

The card itself measures 245mm in length, around the same as the old HD 5850. The big black heat sink on our reference test card stayed reasonably cool during testing, and fan noise was less than the older cards. On the rear of the card is a big selection of connectors. There’s a pair of DVI ports, as you’d expect, but only one is dual-link, while the other is single-link (supporting resolutions up to 1,920×1,200) . These are joined by a full-sized HDMI 1.4a port and two DisplayPort 1.2 mini connectors.

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It’s these latter ports that provide the new features on the card, which are otherwise thin on the ground. HDMI 1.4a is the latest standard and adds support for all the current 3D standards, plus support for resolutions up 3,840×2,160 – often professionally referred to as 4K displays and found in the best digital cinemas. The DisplayPort 1.2 connectors still provide Eyefinity multi-monitor support, but new breakout hubs (more details yet to be announced) will allow you to connect these to DVI or HDMI equipped monitors.

The card draws 151W under load, which requires two PCI-Express 6-pin power connectors. This is the same as the HD 5850, so you’re getting more graphical power per watt. It idles at just 19W, a significant improvement of 50% over the older cards.

The HD 6870 isn’t jaw-dropping, but for those who want to upgrade from a 4000-series, or older, graphics card they do provide a lot of graphical power for the money. Prices have ended up being about £25 cheaper than we were initially led to believe. With performance gains of around 40% over the GTX 460 1GB in our tests, it’s well worth the extra £20.

Rumour has it that ATI’s next generation ‘Cayman’ cards are only just around the corner, but we reckon that these will be priced well beyond the reach of most gamers. For enthusiasts without bottomless pockets, who want a powerful card today, the HD 6870 is the best choice.