One area that the Radeon cards have always been excellent on is their Crossfire scaling performance. Many has been the time we've looked at an otherwise average card and discovered that a pair of them yields a much higher-than-anticipated level of performance.
Given that we know the HD7970 is a total beast of a thing we really couldn't wait to have a go at Crossfire cards. HIS Digital were on hand as always to let us have a pair of cards for testing, and so here we are.
With £800 of graphics cards and a high-end test setup, will the HD7970 Crossfire take us to new heights?
Read on Macduff.
Like PowerColor, HIS Digital seems to be going for an interstellar theme with the current round of packaging. Not a bad visual cue considering the galactic performance available to us.
Yes it's another reference designed card with a different sticker on it. One of the biggest downsides to the early batch of cards is that manufacturers haven't yet got round to mounting their own cooling solutions, and so we are left with a selection of entirely indistinguishable cards.
The HIS includes all the accessories one would expect to find. Bridges, output adaptors and the like.
The switch up next to the Crossfire finger is for dual-BIOS, so you can flash your card safe in the knowledge you wont end up with a very expensive paperweight.
Of course no Crossfire review would be complete without some gratuitous hardware porn shots. As great as dual-GPU cards are, there is something more thrilling and more exciting about two single cards than just one big one. We very much like the looks of a tower stuffed with GPUs, and the black and red colour scheme should fit in with most systems.
Our new LGA2011 bench rig gets its third outing of the day, and the combination of the black and red cards on the black and red Rampage IV certainly looks the part.
2x HIS Digital HD7970
Catalyst HD7970 Drivers 11.12
Intel Core i7-3960X @ 4GHz
ASUS Rampage IV Extreme
3x iiyama Prolite 24"
Windows 7 Ultimate x64
With Crossfire and Eyefinity on test we have two areas in which our overclock can be forced to be reduced, and so it proves. Rather than the high overclock we saw on the single PowerColor, our Crossfire setup tops out at 1050MHz. Still a good increase, but certainly nothing like the cards are capable of.
3D Mark Vantage
Ooh boy what a score. 51000 P-Score just from a couple of the HD7970s. That's 7000 more than a GTX580 SLI setup, which until now is pretty much the weapon of choice for big scores. Even more impressively is that with the Extreme setting enabled the HD7970CF still manages 6000 more than the GTX580SLI. Nothing else comes close. Although we seem to be hitting the limits of either power draw or heat with the overclock.
3D Mark 11
Considering the HD7970 CF setup is well under half the price of a MARS 2 SLI rig, it's amazing how close the scores get. Even the GTX580SLI is bludgeoned to death by the might of the AMD offering.
Alien vs Predator
Such is the incredible performance (and those are words you will hear a lot throughout this review) the HD6990 and GTX580 SLI setups are made to look positively lethargic by the HIS.
Batman Arkham City
Considering we've thrown some very expensive and high performing hardware at Arkham City it's far to say that the game isn't particularly well optimised. Anything that can score 50000 3D Marks but can only 51 in Batman, and that's 6 less than a single card, shows the poor quality of the engine rather than any performance issues of the card. Even in Eyefinity we only gain 6 FPS over a single card. Either it's not very impressive coding skills from Rocksteady, or the developers of the AMD drivers still haven't got their stuff in gear.
Once again the overclocked cards actually score less than the stock ones. Although the stock ones give, by 0.2 FPS, the second best result we've ever seen. Remember that this is Crysis 2 with everything maximised, including hi-res textures, and we're getting 46 FPS in Eyefinity. The MARS 2 got 18. Nuff said we think.
Dirt 3 definitely isn't a fan of dual-GPUs. First we had risible performance from the MARS, and now the HD7970 Crossfire setup is handily beaten by a single card. In fact looking at the Eyefinity score we'd think the second card wasn't doing anything but lowering the score. Disappointing.
Far Cry 2
Wow. It might have been derided a little when it was released, but the Dunia engine has proven time and again that it was an exceptionally good bit of coding. Not only does it take advantage of both cards fully to give us amazing results, but you can have a full eye-candy Eyefinity experience that gives you 115 FPS. Wonderful.
We have some odd results with Mafia 2. The second card doesn't seem to make any difference on a single screen setup, but definitely does when we move to Eyefinity. So both exciting and disappointing in equal measure.
We've gone on about how Metro 2033 only really hits its stride with two GPUs and boy oh boy does the HIS HD7970 prove that to be the case. A whopping 94 FPS at stock and 106 when overclocked. For those paying attention that's better than a MARS 2 SLI setup, for half the price. Unquestionably if you are a fan of 4A Games FPS then this is the setup you need.
Resident Evil 5 - DX9
Resident Evil is nothing if not consistent. No matter what we've thrown at it we always get rewarded. Not so today though. The extra card has gone off to make a coffee or something, because it's certainly not helping our frame-rate.
Resident Evil 5 - DX10
The Direct X 10 rendering path gives us the same as we saw from DirectX 9. No benefits to be found here.
The Witcher 2
This is becoming slightly concerning. We don't mind the odd game not responding well to a Crossfire setup, but The Witcher 2 is one of the newer games on test and yet still doesn't give any performance enhancement from the second card. Remember that although the Eyefinity result looks good, an issue with AMD cards means that Eyefinity only renders a single screen.
Oorah. Look at that bad boy. At stock at least the HIS HD7970 positively chews through Unigine and spits it out, leaving it shocked and confused. 136 FPS. Although, similar to some other games on test, the overclock actually hinders rather than helps.
The story remains the same when we ramp up the image quality.
If you're running two of these bad boys then you definitely need to be running triple screens to get the most out of them. On more than one occasion the extra card made no difference at all to the final frame-rates we saw in games, but it nearly always helped when running at the extreme 5760x1080 resolution of Eyefinity.
That isn't to say that there aren't any issues. Indeed this is one of the more tricky dual card runs we've done. By no fault of HIS Digital we hasten to add. Rather it seems that the drivers are once again the Achilles Heel of the Radeon set up. One day AMD will sit down and realise that it doesn't matter how amazing your hardware gurus are at designing a graphics card when your software guys appear terminally incapable of coding drivers that just work. Sure the poor quality of Catalyst drivers when compared to their ForceWare opponents is so well known it's almost a standing joke, but it's been that way since we can remember and with such an epic product as the HD7970 it's frankly not good enough. Hopefully in the weeks and months to come the game developers and the AMD driver team will lock them selves in a room with a tanker full of Starbucks and not emerge until all the creases are ironed out. We live in hope.
Battlefield 3 wouldn't run at all, The Witcher 2, Resident Evil 5, Dirt 3 and Batman Arkham City all showed better performance with a single card than the Crossfire set up. These aren't games based upon the same engine, nor from similar developers or even in the same genre. If you are buying a pair of these for your favourite game it's definitely worth checking that Crossfire works properly.
However, getting off of our soapbox and looking at those scenarios in which the Crossfire did work properly the results were incredible. It was comprehensively better than a GTX580 SLI setup, which is the same price and has ruled the performance roost since they were released. AMD have made a major leap forwards, producing a setup that, for £800 can give you some of the most eye-poppingly smooth gameplay you could ever hope to see.
So if you are in the market for incredible performance, but don't mind the fact that once again you're stuck with the pretty risible Catalyst drivers then this set up is definitely worth a look. When it works it's unbeatable. It's just not as 'plug and play' as we've come to expect from modern hardware.
For this reason we're awarding it our OC3D Performance Award. As a single card the HIS Digital is as good, and Gold worthy, as any other reference HD7970. In Crossfire though it's a bit pricey and a bit temperamental till the drivers are ironed out.
Thanks to HIS Digital for providing the HD7970s for review. Discuss in our forums.