As in the automotive world, the extreme high-end of computer hardware is almost always fun to look at, and rarely practical to own. With its Ares II, Asus set out to build the fastest graphics card in the world, matched by stunning presentation. The final product was mostly supposed to serve as demonstration that the company could build such a performance-oriented product, even if it was only available in limited quantities (the company claims only 1,000 were made, of which only a fraction made it to the U.S.).
So, why bother looking at it now? Because we had one in the lab, that's why. Oh, and it just so happens that only two samples of the other "fastest dual-GPU card in the world" ever left its manufacturer's lab. That was HIS' Radeon HD 7970 X2 (not X2), and we got both of them last year. Creates a nice little comparison, right? The Ares II offers an additional 50 MHz on the core clock, plus liquid cooling to deal with the incredible heat generated by two Tahiti GPUs.
We previously rounded up HIS' Radeon HD 7970 X2, PowerColor's AX7990 6GBD5-A2DHJ Devil13, and EVGA's GeForce GTX 690 in Radeon HD 7990 And GeForce GTX 690: Bring Out The Big Guns. Now that we have the Ares II, it only makes sense to add it to our round-up numbers. We're using the same benchmark system and drivers to keep the comparison fair. It would have been great to get those other dual-Tahiti boards into the lab to run them with the very latest drivers, but they're both such rare museum pieces that it simply wasn't possible. We settled on turning back the clock and adding Asus's effort. Incidentally, we didn't add Nvidia's GeForce GTX Titan for much the same reason (not that it would have mattered, since one Titan is slower than a GTX 690).
| Nvidia GeForce GTX 690 Vs. The Dual-Tahiti Competition | ||||
|---|---|---|---|---|
| Asus Ares II | HIS Radeon HD 7970 X2 | PowerColor AX7990 6GBD5-A2DHJ Devil13 | EVGA GeForce GTX 690 | |
| Shader Units | 2 x 2048 | 2 x 1536 | ||
| GPU Clock Frequency | 1100 MHz | 1050 MHz | 925 / 1000 MHz (BIOS) | 915 MHz + GPU Boost |
| ROPs | 2 x 32 | 2 x 32 | ||
| GPU | 2 x Tahiti | 2 x GK104 | ||
| Transistors | 2 x 4.31 million | 2 x 3.5 million | ||
| Memory Size | 2 x 3 GB | 2 x 2 GB | ||
| Memory Bus | 2 x 384-bit | 2 x 256-bit | ||
| Memory Clock Frequency | 1650 MHz | 1500 MHz | 1375 MHz | 1502 MHz |
On paper, Asus' Ares II looks good. HIS' Radeon HD 7970 X2 runs 50 MHz faster than PowerColor's Devil13 card at its overclocked BIOS setting, which is why it proved to be the faster board in our original round-up.
We’re testing with our 2012 VGA benchmark system. The driver we're using was the "miracle" update that catapulted AMD's performance out in front of what Nvidia could do with its GK104. As a result, we can draw comparisons between the dual-Tahiti boards and Nvidia's GeForce GTX 690 without worrying about software-based misrepresentations. Overall, the data should look pretty similar using today's beta drivers, at least in the games we're benchmarking.
| Benchmark System | |
|---|---|
| CPU | Intel Core i7-2600K (Sandy Bridge), 32 nm, 4C/8T, 8 MB Shared L3 Cache, Hyper-Threading Enabled, Overclocked to 4.5 GHz |
| Motherboard | Gigabyte Z68X-UD7-B3, Intel Z68 Express, BIOS F10 |
| Memory | 4 x 4 GB Kingston HyperX DDR3-1600 |
| CPU Cooler | Cooler Master TPC 800 with Noiseblocker eLoop B12-PS (PWM) |
| System Drive | Kingston V200+ 480 GB |
| Power Supply | Corsair AX1200i Digital ATX Power Supply, 1200 W, 80 PLUS Platinum |
| Operating System | Windows 7 x64 Ultimate |
| Drivers | Catalyst 12.11 (Beta) and Catalyst 12.9 GeForce 306.97 WHQL |
| Ambient Temperature | 22 °C (held constant) |
| Benchmark Case | NZXT Phantom 820 |
It’ll be interesting to see how these enormous cards fare in a closed case. It’s not easy to exhaust out 500 or more watts of heat.
A Close Look at the Asus Ares II
Asus didn’t cut any corners designing its Ares II. Marketing was likely responsible for the Greek god of war's name on the card. What we want to know is whether the engineers were able to make good on such a bold moniker.
The Ares II basically bears the specs of two Asus Matrix Radeon HD 7970 Platinum cards running cooperatively. Its GPUs are GHz Edition chips, but they ship at factory-overclocked frequencies. Normally, you'd find those ASICs running at 1 GHz with a 1,050 MHz boost state. Asus operates them at 1,050 MHz and then boosts to 1.1 GHz. As we've seen from other boards, the boost clocks are active until the card operates under full load for long enough and the temperatures spike, triggering a clock rate reduction.
Each of the two GPUs has 3 GB of memory, totaling the specified 6 GB. The memory operates at an effective 3.3 GT/s. It goes without saying that this is one hot card.
For that reason, Asus decided to use a hybrid cooling solution for its Ares II. A compact closed-loop water cooler draws heat away from each of the GPUs, while an 80 mm fan in the middle of the card helps keep the memory and power circuity cool.
The Ares II sports a total of four DisplayPort and two DVI connectors. Because its cooling solution is largely liquid-based, none of the rear I/O panel space is needed for ventilation (though that 80 mm blower does recirculate heat into your case). This configuration facilitates up to six displays in Eyfinity without needing a multi-stream transport hub. One of the two DVI outputs is dual-link-capable, which you can toggle using a switch next to the CrossFire connector, depending on the resolutions you require.
As with some of the other dual-Tahiti cards we've tested, Asus' Ares II employs a whopping three eight-pin auxiliary power connectors. These should be able to deliver up to 525 W when you count the PCI Express slot's 75 W-output. Don't think the card can come anywhere close to that level of power draw? You might be surprised to learn it even exceeds it by quite a bit, depending on what you're doing. At least 525 W is enough for gaming.
The Elusive Champion: HIS Radeon HD 7970 X2
The extremely rare HIS Radeon HD 7970 X2 was never fully developed for the market, and consequently never hit store shelves. It employs a three-slot design necessary for cooling two Tahiti GPUs. Most noticeable, perhaps, are the two 9.5 cm fans that sit right over the card's twin graphics processors.
HIS decided to separate each GPU's power supply, going so far as to place them apart from each other on the board's PCB. In comparison, PowerColor uses one shared power circuit on its Devil13. In both cases, the total number of phases is the same: six for each GPU and two for each 3 GB chunk of GDDR5 memory. Magic R30 coils cut down on squealing.
HIS adds a twist to the cooling design. Its Radeon HD 7970 X2 doesn’t use one big sink like the competition, but rather two separate heat sinks that are each attached to one GPU and can be cooled independently. Both GPUs are connected through a Lucidlogix LT22102, which is unfortunately limited to PCI Express 2.0 signaling speeds.
The Beautiful Beast: PowerColor Devil13 Radeon HD 7990
PowerColor was the first to enter the market with its AX7990 6GBD5-A2DHJ Devil13. Since then, PowerColor’s parent company, TUL Corporation, introduced a similar design with slightly lower clock rates. Right now, that model is priced at $900 on Newegg, though it's out of stock. Hardware-wise, it's the same card. Only its frequencies are different.
Just like HIS' Radeon HD 7970 X2, PowerColor designed its Devil13 board from the ground up. It’s also a three-slot card, but instead employs a trio of cooling fans. The middle fan sits at an angle and has a diameter of 75 mm. The two larger fans each have a diameter of 90 mm.
Three eight-pin auxiliary power connectors and the slot together deliver up to 525 W, which is exactly the same as what we've already seen from HIS and Asus, and likewise insufficient when this board is under full load. We'll explore that in more depth shortly. On-board memory comes from Hynix; it can be manually overclocked to just over 1,500 MHz, though PowerColor ships it at a mere 1,375 MHz. PLX’s PCI Express 3.0-capable PEX 8747 connects the two GPUs with 16 lanes to each, along with 16 lanes to the slot interface.
The Voice of Reason: EVGA GeForce GTX 690
EVGA is only selling one version of the GeForce GTX 690. Nvidia's reference design is so good that there isn't much room for improvement. It's fairly thin and, at 1.04 kg, fairly light. Even after the GK110-based Titan's introduction, this dual-GPU board remains a flagship in the company's portfolio.
As we already know, the GTX 690 is built up on two GK104 graphics processors (the same ones used in Nvidia's GeForce GTX 680). Together, both GPUs wield 3,072 CUDA cores (1,536 per chip). The number of texture units and ROPs remain the same too, totaling 128 and 32 per GPU, respectively. Instead of its older PCI Express 2.0-limited NF200 bridge, Nvidia leans on PLX's PEX 8747 to connect its GPUs, enabling third-gen PCIe communication at very low latencies. Each GPU has access to its own 2 GB of GDDR5 memory, attached to an aggregate 256-bit memory bus. Bandwidth is identical to the GeForce GTX 680, at 192 GB/s.
Not everything is equal, though. The GeForce GTX 690's core clock rate is lower than the 680's (915 MHz compared to 1006). Similarly, the expected GPU Boost clock you'd expect to see from a GeForce GTX 690 is slightly lower as well (1,019 MHz). Two eight-pin auxiliary power connectors should deliver enough power for this card. Add in the interface's 75 W ceiling, and it has access to up to 375 W. The 690's predecessor, the GeForce GTX 590, used even more power and was rated at 365 W.
3DMark 11
As mentioned, we're using an older driver on Asus' Ares II in order to draw fair comparisons to the other ultra high-end cards we tested previously. The Radeon HD 7000-series boards received a massive performance boost back when AMD released its Catalyst 12.11 package, allowing Tahiti-based products to compete with and often beat Kepler-based cards that were previously faster.
Asus' Ares II demonstrates that it doesn’t just outperform the competition on paper, but instead kicks off our testing by drawing ahead in two different 3DMark detail levels.


Unigine Heaven 2.5
We’re benchmarking these graphics cards using the highest resolutions and settings. Slower single-GPU boards cannot compete when it comes to these demanding combinations of resolution and graphics quality. They just aren't powerful enough.


Unigine Sanctuary
The finishing order stays the same. The Ares II pulls ahead a bit more due not only to its higher clock rate, but also its higher memory frequency.


Gaming Benchmarks
Once again, we're only using the triple-monitor setup for testing dual-GPU cards because the single-GPU offerings cannot handle 5760x1080.
Because the drivers are, in fact, a little older, we ran the Ares II and EVGA GeForce GTX 690 (which we still had on-hand) using the very latest software from both companies to confirm our findings. Gladly, there's wasn't much of a difference. In fact, the delta was small enough in these older titles that we're comfortable chalking them up to normal variation. Now, had we folded something like Tomb Raider or BioShock Infinite into the suite, we would have run into trouble.
As is, our benchmarks consistently show the Ares II inching out HIS' Radeon HD 7970 X2. Again, Asus' exhibition card doesn't just have an edge on paper, but also in the real world (more so because Asus managed to ship a few; HIS didn't).
Alien vs. Predator


Batman: Arkham City


Battlefield 3


Metro 2033


Crysis 2: DirectX 11 + HD Textures


Temperatures
The Ares II’s closed-loop liquid cooler isn't particularly quiet, but it does effectively keep the card cool. That's quite an accomplishment.


Noise
We used to measure noise using a regularly-calibrated sound level meter, namely, the SL-400 with data logging by Voltcraft. It only provides good results between a limited frequency range, though. It’s practically useless for frequencies higher than 10 kHz. We needed something else to help us represent the impact of coil squealing. PowerColor's AX7990 6GBD5-A2DHJ Devil13 almost drove us insane with its tinnitus-invoking noise last year. Back then, we decided to use a studio microphone that had been calibrated for our purpose and hung vibration-free. We use the same setup to test Asus' Ares II.

PowerColor would have done better at idle if it hadn’t been for the inductor noise that's above the frequency threshold of modern sound level meters. When the squealing is taken into account, the AX7990 Devil13 ends up in second-to-last place. Together, the Ares' two fans generate a base noise level that's slightly higher than the air-cooled cards at idle.

EVGA's well-built GeForce GTX 690 clearly wins out against the AMD-based competition under a gaming load. It really shows that a pair of GK104s generate a lot less heat than two Tahitis. The noise levels of all three cards remain acceptable, though. PowerColor's AX7990 6GBD5-A2DHJ Devil13 brings up the rear in this metric. And two high-end cards from Nvidia manage manage to beat the liquid-cooled Asus Ares II.

HIS' cooler runs out of capacity under full load, requiring that the card spin up its fans and generating more noise than PowerColor's AX7990 6GBD5-A2DHJ Devil13. Then again, anything above 50 dB(A) is just too loud. EVGA's GeForce GTX 690 is the only air-cooled dual-GPU card that manages to stay under this noise level. Meanwhile, Asus' cooling solution shines.
Most systems don't usually see this sort of workload though, so its relevancy is limited to the folks mining for bitcoins (perhaps not a bad idea right now, given what's going on in Cyprus). Without question, the most important charts are our results at idle and under the influence of Crysis 2.
Power Consumption
And here's where pushing two power-hungry Tahiti GPUs as far as they'll go comes back to bite you. If our power consumption benchmarks were Star Wars, then Asus' Ares II is the evil Emperor. We're not sure if the company's engineers were paying attention to the PCI Express electromechanical specification or what. But the card goes well over the 525 W that one 16-lane slot and three eight-pin connectors are rated for. It comes close to doubling what a GeForce GTX 690 uses, and exceeds HIS' worst-case measurement by more than 50 W.
Bear in mind that those are card-only numbers; they aren't representative of the entire system. While we'll acknowledge that Asus built-in some headroom for overclocking, and suggest that you can bring power consumption down a bit by undervolting the Ares' GPUs, these are the numbers you'll see out of the box. Brutal.





Asus ships this flagship card in a briefcase that you might expect to see a spy carrying around in a movie. Is it full of money? Does it contain the pieces for a sniper rifle? Or will you find the Ares II in there? The low profile, unassuming look might not have been Asus' intention, but it certainly fits well. When you combine this card's high price and gratuitous power consumption, we're not surprised the company only chose to manufacture 1,000 of them.
Apparently, it didn't have any trouble selling them, though. At least here in the U.S., they aren't available anymore.
Asus did hit its target of manufacturing the fastest dual-GPU graphics card on the planet, though. HIS could have worn that crown if the company had put its prototype into production. The Radeon HD 7970 X2 was overclockable, and might have matched the Ares II. However, Asus took that additional step, earning it a well-deserved, if largely symbolic, victory.
There's one other variable we didn't bring up in this story, but have in the past: using frame limiting to address micro-stuttering. AMD needs to learn from the RadeonPro tool we've tested previously and further develop what that utility does to smooth out performance. Software advances would go a long way toward making AMD's real-world experience a lot better.
Make no mistake, Asus' Ares II is the fastest graphics card around. But it really only performs on the GeForce GTX 690's level once you use frame limiting to get stuttering under control. Nvidia's GeForce GTX 690 is less expensive and consumes a lot less power under full load. If you missed out on your chance to own an Ares II, let that be your consolation. Asus' board is bigger, badder, and commands more attention, but almost a year after its launch, the GeForce GTX 690 remains the most elegant high-end card we've ever used.













