AMD Radeon HD 7970 Duel - ASUS vs. Sapphire

State of the GPUnion

Back in February, we took a look at the first AMD 28nm GPU, the 'Tahiti'-based Radeon HD 7970. As the first card utilizing AMD’s next generation GPU architecture, GCN (Graphics Core Next), as well as the first card based on a GPU with a 28nm process technology, there was much anticipation for how it would perform.

While we were impressed with the Radeon HD 7970’s overall performance, which was a clear winner when pitted against NVIDIA’s at-the-time flagship model, the GTX 580, since then, NVIDIA has retaliated with the release of their own 28nm GPU, the ‘Kepler'-based GeForce GTX 680.

With a bit of extra time to develop their own 28nm chip, NVIDIA’s Kepler architecture has so far proved more successful than AMD’s, with our benchmarks showing the GeForce GTX 680 pulling ahead of the Radeon HD 7970 in quite a few tests. Compounded with NVIDIA’s lower SRP for the GTX 680, which retails for US$499, compared to the HD 7970’s US$549 (locally, the price difference isn't as pronounced, with the HD 7970 retailing for S$849, and the GTX 680 going for S$829), NVIDIA has put AMD on the ropes and under pressure.

AMD has since announced a price cut on all HD 7900 series graphics cards, reducing the suggested retail price of the HD 7970 to US$479, and even throwing in three games: Dirt Showdown, Nexuiz and one of 2011’s top titles, Deus Ex: Human Revolution with The Missing Link DLC with every Radeon HD 7900 series card at selected retailers. For now, we haven't seen the price cuts trickle down to the local market, but expect reductions in the coming months.

The Eyefinity Factor

Of course, AMD still holds some advantages. While NVIDIA has improved its multi-display support, with the GTX 680 now supporting up to three 3D displays, plus a fourth non-3D display, on a single card, AMD’s Eyefinity technology remains the king, with the HD 7900 series capable of driving up to six 3D displays on a single card.

And, while NVIDIA’s GTX 680 is the best reference card we’ve tested, it didn’t completely obliterate the HD 7970, which was close enough, especially on more taxing benchmarks that we could theoretically see it making up lost ground in an overclocked scenario. That is, of course, if the Radoen HD 7970 overclocks better than the GTX 680.

With that in mind, today we take a loook at two high-end, factory-overclocked Radeon HD 7970s, one from ASUS and one from Sapphire. With higher GPU core and memory clock speeds and each manufacturer's own tweaks, we’ll be able to get an idea of the real potential of the Radeon HD 7970.

As a side note, MSI’s Lightning Edition Radeon HD 7970 was originally scheduled to appear as the third entrant in this duel (Mexican Standoff?), but our review unit was faulty, so we’ll be revisiting that one when we have a proper working replacement unit.

The Radeon HD 7970 Cards

ASUS Radeon HD 7970 DirectCU II TOP 3GB GDDR5

Overclocked to a GPU Core speed of 1000MHz (75MHz higher than reference), with 5600MHz memory (100MHz higher than reference), ASUS’ champion in this duel also features an improved version of their DirectCU (Direct Copper) thermal cooling system to adapt to this high-end GPU. DirectCU utilizes a dual-fan design with six copper heatpipes in direct contact with the GPU, just as the name implies. Although ASUS claims that DirectCU II improvements include a 20% larger dissipation area and an overall quieter operation than previous versions, take note that the DirectCU II series of coolers have been around for close to a year now. So don't get consumed by the marketing figures but we'll figure out if the cooler is any good later in our results section.

While all Radeon HD 7970 cards feature six-monitor Eyefinity support, most will require a DisplayPort 1.2 MST (Multi-Stream Transport) capable hub to be connected to provide enough monitor connections. This ASUS card however, features six ports on the back plate itself, consisting of two DVI ports and four full sized DisplayPorts. The HDMI port found on the reference HD 7970 has been removed to make way for these ports.

On most Radeon HD 7970 cards, you'll find a dual-BIOS toggle switch on the top of the card. On this ASUS model, this switch has been reconfigured into a DVI switch that changes between dual and single link DVI. To run in six-monitor mode, the DVI switch must be set to single link mode. Dual-link DVI is required to drive very high resolution screens like the 30-inch monitors which usually have a native resolution of 2560 x 1600 pixels. If you'll require this, then you're limited to five screens maximum. So the six-monitor support isn't exactly fuss free and some caveats apply to the monitor configurations used. 

ASUS has also brought its DIGI+ VRM digital power delivery design, first seen on its motherboards, to the Radeon HD 7970 DirectCU II TOP. DIGI+ VRM is applied via a 12-phase power design that uses digital voltage regulators to increase power efficiency, widen the voltage modulation range, and improve overall stability and longevity. Power delivery components utilize ASUS’s Super Alloy Power formulation, which reinforces capacitors, chokes, and MOSFETs with better manufacturing and materials to increase heat tolerance and stress resistance.

As with all ASUS cards, their GPU Tweak utility is included for easy overclocking as well as all your monitoring needs.

Sapphire Radeon HD 7970 OC 3GB GDDR5

Sapphire’s offering in this Radeon HD 7970 duel is a factory-overclocked GPU core speed of 950MHz (25MHz higher than reference), with 5700MHz memory (200MHz higher than reference). It uses Sapphire’s Dual-X cooling system, which features five heatpipes strategically located inside a 230mm-long heatsink packed full of aluminium fins.

Unlike ASUS, Sapphire keeps the functionality of the dual-BIOS switch on their Radeon HD 7970. The first setting, which is the shipping default, sets GPU core speed to 950MHz and memory to 5700MHz DDR, while the second setting pushes it to 1000MHz and 5800MHz DDR respectively, putting it on par with the ASUS’ model (in fact, memory clock speed is 200MHz higher in DDR rates). Going hand-in-hand with the increase, the second BIOS also loads a more aggressive fan speed profile and enables a higher GPU voltage to be set.

Connections wise, Sapphire doesn't deviate from AMD's reference template, offering two Mini DisplayPorts, one HDMI port and one DVI port.

For the tinkerers, Sapphire includes their own TriXX overclocking utility with the card.

Test Setup

As usual, the following are the specs of our trusty graphics card test bed system:

• Intel Core i7-975 (3.33GHz)
• Gigabyte GA-EX58-UD4P motherboard
• 3 x 1GB DDR3-1333 G.Skill memory in triple channel mode
• Seagate 7200.10 200GB SATA hard drive
• Windows 7 Ultimate 64-bit

The list of benchmarks used:

• Futuremark 3DMark 11
• Unigine Heaven v2.1
• Battlefield: Bad Company 2
• Crysis Warhead
• Far Cry 2
• Crysis 2
• Batman: Arkham City
• Dirt 3
• S.T.A.L.K.E.R.: Call of Pripyat

We tested both cards at their out-of-the-box settings; as such, the Sapphire Radeon HD 7970 OC is using its default, factory-shipped, BIOS 1 setting, which gives it a GPU core speed of 950MHz (25MHz higher than reference), and 5700MHz memory (200MHz higher than reference). Naturally, setting it at BIOS 2 setting would enable it to rival the ASUS graphics card, but as you'll see in our results on the following pages, the difference between the two cards are rather miniscule to be concerned about and probably not worthwhile the extra heat output and power consumption.

3DMark 11 Results

Before we get into the actual gaming benchmarks, lets take a look at a couple of dedicated GPU benchmarks first. First up, 3DMark 11, which tests various DirectX 11 functions like tessellation and DirectCompute to put the GPUs through their paces. While both the ASUS and Sapphire HD 7970 outperformed the reference AMD card, their scores were not that impressive, with only a 3% and 1% performance gain respectively, on both the Performance and Extreme presets.

Additionally, NVIDIA’s reference GeForce GTX 680 was able to beat both cards by about 10% on both presets.

Unigine Heaven 2.1

The Unigine Heaven 2.1 DX11 benchmark heavily stresses tessellation. Results were interesting here, with the two overclocked HD 7970s posting quite underwhelming results without anti-aliasing, improving on the reference card scores by only 2-3% each.

However, with anti-aliasing set to 8x, both ASUS and Sapphire saw a 10% increase when compared to the reference card across all resolutions.

Against the NVIDIA GeForce GTX 680, at resolution of 1680x1050 and 1920x1200 pixels, all three cards performed within 2% of each other. However at the highest resolution of 2560x1600 pixels , the Radeon HD 7970s started pulling ahead, maintaining a 3% difference between each other, but outperforming the GTX 680 by up to 15% with 8x AA. Some of this difference may be due to the GTX 680’s reduced memory buffer size.

Battlefield: Bad Company 2

While Bad Company 2 is starting to show its age, its DX11 Frostbite 1.5 engine is still a fairly taxing test, particularly at stressing a GPU’s geometry shading power. In the past AMD cards have traditionally been stronger in this benchmark, however, times seem to be changing as the GTX 680 once again beat both overclocked HD 7970 cards.

At lower resolutions, the Radoen HD 7970s performed within 2% of each other, but this time showing a slightly stronger 8% improvement against the reference card. However, both were behind the GTX 680 by about 7%. At our highest resolution of 2560x1600 pixels, that gap grew even wider, with the GTX 680 able to outperform both HD 7970s by a massive 17%.

Crysis Warhead

In the tessellation heavy Crysis Warhead, both ASUS and Sapphire finally got the better of NVIDIA, outperforming the GTX 680 by about 5%, while again performing within 2% of each other. Against the reference card, we saw a roughly 7% performance gain.

Far Cry 2

Unfortunately, Far Cry 2 once again saw the overclocked Radeon HD 7970 cards fall behind the GeForce GTX 680. In a now familiar pattern, we saw a steady 6% gain against the reference card, while the GTX 680 outperformed the HD 7970s across the board, with an average of 10-12% better performance on all tests.

Crysis 2

Moving on to the toughest game in our benchmark list, we once again saw both cards performing within 2% of each other, and 8% better than the reference card.

However, things were different when compared to the GTX 680. The GTX 680 slightly outperformed both HD 7970s on the lowest resolution of 1680x1050 pixels resolution, and was very strong at 1920x1200, where it won by a huge 14% margin. At the resolution of 2560x1600, the cards were at level playing field - all performing quite badly with sub-30 frames per second, although ASUS’ Radeon HD 7970 actually slightly outperformed the GTX 680 by a hair. The NVIDIA card probably lost steam due to limited frame buffer size. We'll have to test the 4GB editions in time to come to verify if this is the only cause for the performance dip at that resolution.

Batman: Arkham City

Batman: Arkham City’s was optimized for use with NVIDIA's PhysX, which generally skews results in its favor. As expected, both HD 7970’s struggled and, for the first time, were unable to outperform the reference card. In fact, they posted identical scores to the Radeon HD 7970’s as well as its little brother, the Radeon HD 7950. Meanwhile, the GeForce GTX 680 outperformed both cards by about 15%. The lesson here? If you want to play Batman: Arkham City (or other PhysX enabled games) at High Settings, get an NVIDIA card.

Dirt 3

In our Dirt 3 tests, the ASUS Radeon HD 7970 slightly outperformed Sapphire’s, beating it by about 4% compared to the usual 2% difference. ASUS was also able to gain about 6% on the reference card, while Sapphire improved on it by about 2% only.

However, those scores were all overshadowed by the GTX 680’s whopping 20% lead in all resolutions.

As a side note, we were unable to get any of the AMD cards to run at 8x anti-aliasing in Dirt 3, but we suspect this may be due to a problem with the benchmark utility rather than the cards themselves as we had no problems with the AMD cards running 8x anti-aliasing on Far Cry 2 or Battlefield: Bad Company 2.

S.T.A.L.K.E.R.: Call of Pripyat

In our S.T.A.L.K.E.R.: Call of Pripyat benchmark, the overclocked HD 7970 cards only showed marginal performance gains against the reference card on the less taxing Day Run with anti-aliasing off, averaging about 1% better. However all three cards were already churning out frame rates at over 150FPS. On the other hand, they trailed behind the GTX 680 by about 9%.

On the more intensive Sun Shafts Run with anti-aliasing set to 4x, both cards fared much better, improving on the reference card scores by about 3% while also getting the better of NVIDIA, with about 4% better average FPS on the lowest resolution, and improving as we bumped up the resolution, with the ASUS claiming a considerable 12% margin of victory over the GTX 680 at the resolution of 2560x1600 pixels.

Overclocking

For our overclocking efforts, we were able to push the ASUS Radeon HD 7970 up to 1245MHz at the core with memory running at 6800MHz DDR. On Sapphire, we were able to get to get its GPU core up to 1211MHz and memory to 6800MHz DDR. For both of these settings, we had to increase voltage to 1.185mV, up from the default value of 1.174mV.

For our efforts with ASUS, we were rewarded with a roughly 16% improvement on 3DMark 11’s Performance preset, while the card really shined on the Extreme setting, showing a 22% increase in performance compared to its factory overclock setting.

With Sapphire, our gains were even bigger, with a 17% increase on 3DMark 11’s Performance setting, and a massive 24.5% increase on Extreme.

Compared against each other, ASUS slightly edged out Sapphire with about a 1-2% lead in their final overclocked benchmark scores.

Against the overclocked GTX 680, both the Radeon HD 7970 cards lost in the Performance preset, with the NVIDIA card still holding pole position with just a 2.5% lead. However, the AMD camp turned the tables when it came to the higher resolution and tougher Extreme preset, with ASUS posting a substantial 7% margin of victory, and Sapphire at 5% over the GTX 680 respectively. Not a bad match-up at all and it shows that the custom designed cards from the respective vendors can offer something as enticing as the GeForce GTX 680 in certain respects.

Temperature

Both cards are running somewhat similar cooling systems, utilizing a dual-fan cooler with multiple cooling pipes in direct contact with the GPU. ASUS’s DirectCU II boasts six cooling pipes, while Sapphire’s Dual-X uses only five. Despite this, Sapphire was the winner here, reaching a breezy 62 degrees Celsius at load levels, compared to ASUS' 69 degrees, which was only 3 degrees cooler than the reference design.

Power Consumption

We were quite shocked by the power consumption of the ASUS Radeon HD 7970 Direct CU II TOP, which increased 15% compared to the reference model. Considering it averaged only an 8% gain in performance, this was a little disappointing.

Sapphire, on the other hand, increased power consumption about 8% over the reference card with an average 6% increase in performance on our benchmarks - a much more acceptable result. Besides, the actual difference between the ASUS and Sapphire card are hardly discernable. If you really need the performance levels of the ASUS, you still have the BIOS 2 option on the Sapphire card to toggle and you don't have to pay a hefty price for it.

ASUS or Sapphire?

While both of these cards are based on the same high-end GPU, they represent opposite ends of the spectrum in their manufacturer's approach. Compared to the reference card, ASUS has gone all out, beefing up the card, changing the configuration of the connections, changing the functionality of the BIOS toggle switch and adding a hefty backplate resulting in the card taking up three expansion slots at least. Sapphire, on the other hand, kept things mostly stock, adding just their Dual-X cooling system.

When it comes to price, the cards also sit on opposite ends of the spectrum. The ASUS model sits at the top of the heap, and will set you back a considerable S$879 locally. Meanwhile, Sapphire's model currently retails at nearly S$60 less at $822.83. In fact, Sapphire's SRP is listed at even less than AMD's reference card, which is currently priced at about S$849, although we expect this to change in the near future to reflect the US price cuts.

In our benchmarking, we saw ASUS consistently perform about 2% above Sapphire. However, we tested Sapphire at the default BIOS 1 option, which sets the GPU core clock speed at 950MHz with 5700MHz DDR memory. At the flick of a switch, the BIOS 2 option will boost those numbers to 1000MHz and 5800MHz DDR respectively, which puts it in line with ASUS' specs (in fact, memory clock speed is 200MHz DDR higher than the ASUS card). Based on our results, we can confidently say that with the Sapphire card on BIOS setting 2, it should benchmark very close to what ASUS was giving us.

When it comes to overclocking, we give the nod to ASUS, as there's slightly more room to work with at the top, producing higher max overclock speeds. Even though we found Sapphire's Dual-X cooling system to be slightly better than ASUS's, neither card was ever in danger of overheating. Likewise, both cards acoustic levels were acceptably low, but despite both manufacturer's claiming improved, quieter performance, we weren't blown away by either one.

In terms of flexibility, ASUS is also the winner as, Sapphire's model doesn't offer anything more than what you get on the reference Radeon HD 7970, whereas ASUS gives you the option for connecting six monitors without requiring any additional hubs or adapters.

Ultimately, if you're looking for the best value custom designed Radeon HD 7970, Sapphire is without a doubt the best choice, especially considering that it's currently cheaper than AMD's reference card. If you're looking to hook up six monitors, you want to push your settings to the absolute max, or you just want a card built like a tank, ASUS is the one.

...or NVIDIA?

While this duel was between two AMD Radeon HD 7970 cards, it just wouldn't be complete without a final say about how they compared to NVIDIA's GeForce GTX 680.

In our testing, we often saw NVIDIA's reference GeForce GTX 680 beating our two overclocked HD 7970 cards. While this may seem like it makes NVIDIA the obvious choice for this generation of graphics cards, consider that most of the results (the exception being Batman: Arkham City, which is optimized for NVIDIA cards) in which NVIDIA scored a significantly large margin of victory were in resolutions lower than the 2560x1600. On these tests, both of our Radeon HD 7970 cards were well above the target 60 FPS average that most gamers aim, making any extra gains by the GTX 680 insignificant in terms of actual user experience.

In fact, extremely high frame rates can be quite undesirable as tearing can start to become very obvious at over 100FPS on a 60Hz refresh rate display, but NVIDIA's new generation of cards have adaptive V-Sync technology to counter that. The extra frame rates will of course also come handy if you intend to pursue 3D gaming and this is where NVIDIA has a distinct advantage.

When we looked at more taxing scenarios, our overclocked Radeon HD 7970 cards performed marginally better at times, surpassing NVIDIA's GTX 680. For high-end cards such as these, we expect you will be wanting to run the latest and most demanding games on them, and as such, the choice between AMD and NVIDIA becomes a lot less clear. The more we pushed the cards, the better the Radeon HD 7970 cards seemed to perform. This is most obvious in our max overclock 3DMark 11 tests. On the fairly low-end Performance preset, which runs at 1280x720 pixels resolution, the GTX 680 was untouchable, attaining a score of over 9500. However, on the demanding Extreme preset, which runs at 1920x1080, our Radeon HD 7970 were able to surpass the GTX 680 marginally.

Of course, it's unfair of us to compare vendor customized AMD cards to a reference NVIDIA card. We'll return to the customized NVIDIA cards at a later date (we're especially interested in seeing how the GTX 680 with a higher memory buffer will perform), but for now at least, it does seem that if you're planning on playing at the highest settings and resolutions, you shouldn't count the Radeon HD 7970 out. They certainly have plenty of steam to compete, especially after the new adjusted pricing.

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