HIS 7970 3GB review full review

Graphics chip giants nVidia and AMD seem to have dodged their usual year's-end raft of new releases in 2011. But that does mean we have a rather more exciting start to 2012 than we've been used to from previous years, as the two graphics specialists roll out their latest technology. 

First to turn in its hand is AMD, with the AMD Radeon HD 7970. This is the high-end product from AMD’s new ‘Southern Islands’ series, and answers to the codename Tahiti. The Southern Islands chips are the first chance we've had to see AMD's new grammatically twisted Graphics Core Next architecture.

Historically, the first PC graphics cards were little more than pretty front ends, Potemkin Villages relying on the grunt of the CPU to actually do the real work. 

But while CPUs were strong at mathematical calculcations, they lacked the specialised functions necessary to create sophisticated graphics. This changed in 1999 with the launch of nVidia's GeForce 256, a product that gave birth to the dedicated GPU. 

Subsequent cards have had increasingly powerful GPUs that have been kitted out with better tools for rendering graphics. That's all very well, but in recent years graphics cards have started to struggle more with the complex sums and calculations needed to create today's games. Neither general-purpose CPUs nor the mathematically-challenged GPUs are able to keep up with the fiendish amounts of figures being called upon by modern game developers. 

Again, nVidia has been the company that has tried to change the landscape, and its 2010/2011 Fermi architecture was carefully designed to slice through the heavy maths. 

AMD's new launch

With its new launch, AMD has gone boldly down this route too, throwing out its VLIW (Very Long Instruction Word) architecture in favour of Graphics Core Next. This new technology is much better at organising its workload and planning which instructions can work with each other, and AMD has carefully announced it in advance.

The new architecture was uncovered in depth last summer, half a year before the release of the first actual products. This gave developers more time to create future projects with its GCN technology in mind.

Created using AMD's new 28nm manufacturing process, and representing the main showpiece for the new architecture, the AMD Radeon HD 7970 comes with some teeth-crunching specifications. 

The most powerful card in the previous range was the AMD Radeon HD 6990. That product, however, comprised two GPUs, so it makes the most sense to compare the 7970 with the similarly-named single-GPU 6970. That leaves plenty of room for a future dual-GPU version of the 7970, which we guess could be called the 7990. 

Whilst the 6970 came with 2GB, the HIS 7970 comes with an extra gigabyte of memory – making 3GB in all. This is a hefty amount, particularly given that the limitations of dual-GPU solutions tend to dilute their overall memory complement; although the 6990 had 4GB on board, mirroring of content means that it would often have been able to make full use of just 2-3GB of its memory rather than the full 4GB. 

With that in mind, it may well be that the HIS 7970 has the most practically usable memory of all. The RAM is GDDR5, so it effectively quadruples the memory clock - the base figure of 1375MHz gets boosted to a fantastic 5500MHz. 

The default memory clock is actually the same as on the 6970. This HIS 7970, though, goes one better, stretching the memory interface from 256-bit to a beautifully wide 384-bit. This results in a boost in the memory bandwidth from 176GBps (in the case of the 6970) to 220GBps. 

Throw in a core clock speed of 925MHz and 32-bit ROPs (Raster Operation Pipelines) that work with considerably more zip than before, and it adds up to a very speedy card. The new design also allows for a potential 2048 stream processors - a 33% increase on the 1536 of the 6970.  

The AMD Radeon HD 7970 is the first card to support DirectX 11.1. The extra 0.1 increment is no cause for feverish celebrations, though. It introduces enhancements to 3D audio and to video, along with a few other tweaks to game visuals. Target Independent Rasterization is probably the most notable of the latter additions, and should help in anti-aliasing. In truth, though, there's nothing essential in DX 11.1. It's certainly not reason enough to buy a new card if you weren't going to do so already. 

The HIS 7970 does have some interesting features of its own. Partially Resident Textures is a better way of using textures, and involves turning them into smaller pieces so that it's easier for a game to ignore any bits of the texture that won't be seen (and so, therefore, don't have to be drawn, wasting valuable resources). This is likely to be seen to good effect in the future, although it will be up to games developers to implement it. 

The HIS 7970 supports version 3.0 of PCI-E. For those who buy suitably equipped motherboards, it'll be possible to run the 7970 over the faster interface. We didn't have a PCI-E 3.0 motherboard with which to test it, so can't comment on the potential increase in speed. 

This is likely to depend on the applications you use, though. Typical games are currently unlikely to see a giant difference in performance, although on some titles 5-10% may well be achievable based on the figures. 

HIS 7979 3GB version

Our HIS version of the 7970 was fairly standard, offering a DVI connector along with an HDMI and two Mini DisplayPort connectors. 

The power needs are typical for a high-end card, and you'll need a 6-pin and an 8-pin connector spare on your PSU. It has a TDP of around 225W, which isn't particularly high given the power on board, although HIS does insist that a 500W or greater PSU is used.

That low TDP figure does suggest a bit more grunt could have been eked out of this board. The card is reasonably loud when under load, measuring 45dB against the 43dB typical for a standard GTX 580.

Testing these brand-new cards is often tricky, since we can expect a certain amount of improvement once the games developers start getting to grips with the technology. 

In this case, however, many of the card's differences were known far in advance, so in theory current titles should already be able to get something from the card.

We've conducted a new set of tests to accompany the latest round of graphics cards, and these work at higher detail levels, thus revealing larger differences between the cards. 

In Battleforge, the HIS 7970 produced scores of 68.2 and 47.4 frames per second at 1920 x 1200 and 2560 x 1600 respectively. This places it some distance behind the GTX 590 (102.3 and 60.9fps), but considerably ahead of the 6970 (51.9/37.0fps). 

On Crysis 2, the HIS 7970's figures at the same resolutions come out as 39.7 and 25.9fps respectively. These figures are low in any case, and the differences are smaller.

Nonetheless, the GTX 590 once more has a solid lead with figures of 47.9 and 28.5fps. The older 6970 is barely playable, with figures of 24.3 and 15.6fps. 

In Stalker: Call of Pripyat, the situation is similar to that of Battleforge, and the 7970's figures of 78.8 and 57.1fps are beaten comfortably by the GTX 590 (92.7 and 63.2); but sprint ahead of the 6970's (56 and 36.9fps).


HIS 7970 3GB review: Specs

  • AMD Radeon HD 7970
  • 3GB GDDR5
  • 925MHz core clock
  • 1375MHz memory clock (5500MHz DDR effective)
  • 400MHz RAMDAC
  • 384-bit memory interface
  • 2048 stream processors
  • 128 texture units
  • 32 ROP units
  • PCI-E interface
  • 1 x 6-pin & 1 x 8-pin power connectors
  • DirectX 11.1
  • 1 x DVI, 1 x HDMI, 2 x Mini-DP