AMD Radeon HD 7870 review

AMD has taken an unconventional route with its latest generation of graphics cards, first unleashing the range-topping Radeon HD 7970, then following it up with the mid-range HD 7700 cards. Now that hefty gap in between is being filled by the Radeon HD 7870 and HD 7850, codenamed Pitcairn.

As expected, the HD 7870 slots in neatly beneath the high-end cards: 2.8 billion transistors, down from 4.3 billion, and the stream-processor count has been reduced from 2,048 to 1,280. That means there are 20 Graphics Core Next clusters rather than the 32 found in AMD’s fastest cards.

The memory bus has been narrowed from 384-bit to 256-bit, and there’s only 2GB of RAM rather than 3GB. The HD 7870 has one ace up its sleeve, though – just like the HD 7770, it emerges from its box with a mighty 1GHz core frequency.

It sounds like an intriguing mix, and the HD 7870 delivered a solid set of benchmark results. An average of 56fps in our 1,920 x 1,080 Very High quality Crysis test is 4fps better than last year’s HD 6970, 5fps behind the HD 7950 and the same as last year’s top single-core card from Nvidia, the GTX 580.

In Crysis 2 at 1,920 x 1,080 and its highest quality settings, the HD 7870 averaged 43fps; the HD 6970 could manage only 27fps and the GTX 580 only 29fps. In Just Cause 2, at 1,920 x 1,080 and Very High quality, the HD 7870 averaged 88fps – the same as the HD 7950 – and in DiRT 3’s toughest test its result of 73fps is only 7fps behind the GTX 580.

The HD 7870 also has the legs to play at higher resolutions and across multiple screens, although not necessarily at the highest settings. With Crysis running at Very High quality and with 4x anti-aliasing on a 30in, 2,560 x 1,600 screen, it averaged 28fps. We had to turn the game down to its High quality level to get it running at a playable 36fps across three panels and 5,760 x 1,080. We found similar performance in Crysis 2 on our 30in screen: to extract a playable 31fps in our 30in screen, we had to forego the Extreme and Ultra quality settings, instead sticking with Very High.