Sapphire HD 7970 3GB Video Cards in CrossFire Overclocked

Two AMD Radeon HD 7970's is going to be the most common CrossFire setup, so we take the time to see how overclocking goes.

Published Wed, Jan 25 2012 10:37 AM CST   |   Updated Tue, Nov 3 2020 7:01 PM CST
Manufacturer: Sapphire


Sapphire HD 7970 3GB Video Cards in CrossFire Overclocked 02 |

With the AMD Radeon HD 7990 video card not out yet and still a few months away, if you're looking for some dual GPU action with the new HD 7000 series, then you're going to want to look down the path of CrossFire. Already impressed with what the HD 7970 can do in CrossFire the next thing we wanted to do was see what happens when we take the time to overclock the video cards.

So far we've had some good success when it comes to overclocking which we looked at in our HIS HD 7970 and XFX HD 7970 Black Edition Double Dissipation review. Adding a second card into the mix is known for limiting overclocking ability as cards are placed together and more heat is generated. Those numbers are then amplified due to the added voltage being thrown through the core of each GPU.

Since we've already looked at the Sapphire HD 7970 in our original CrossFire review, we won't need to have a look at the card again. Instead we'll get straight into the testbed setup and quickly cover how we went with the overclock. Once we've done that we'll just get straight into the performance.

So with that all said and done let's get into it and see what's going on with CrossFire HD 7970 overclocking.

Benchmarks - Test System Setup

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We would like to thank the following companies for supplying and supporting us with our test system hardware and equipment: Intel, ASUS and Corsair.

On the testbed side of things there's nothing out of the ordinary and everything should be fairly self-explanatory. On the comparison side of things the main thing we want to look at is how overclocking CrossFire performance compares to stock CrossFire performance. Along with that we've also included our three-way CrossFireX results to see if we're able to close the gap much when it comes to performance.

We've also got the single HD 7970, HD 6990 and the GeForce GTX 580 from NVIDIA. Before we get into the performance side of things we want to look at how we went with overclocking. Firing up our trusty Afterburner utility we're able to adjust our voltage on the GPU to 1.299v and then proceed to bump the core and memory clock speeds up.

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Looking above you can see the clocks we ended up running at. We pushed the core on each card up 150MHz to 1075MHz while the 3GB of GDDR5 on each card was pushed up a massive 1100MHz QDR bringing the final memory clock in at 6600MHz QDR.

This is a nice boost in performance that is timed two thanks to being in CrossFire. Let's see just what kind of performance this overclocked setup brings us while also finding out what goes on in the heat, noise and temperature department.

Let's get started!

The FPS Numbers Explained

When we benchmark our video cards and look at the graphs, we aim to get to a certain level of FPS which we consider playable. While many may argue that the human eye can't see over 24 FPS or 30 FPS, any true gamer will tell you that as we climb higher in Frames Per Seconds (FPS), the overall gameplay feels smoother. There are three numbers we're looking out for when it comes to our benchmarks.

30 FPS - It's the minimum number we aim for when it comes to games. If you're not dropping below 30 FPS during games, you're going to have a nice and smooth gaming experience. The ideal situation is that even in a heavy fire fight, the minimum stays above 30 FPS making sure that you can continue to aim easily or turn the corner with no dramas.

60 FPS - It's the average we look for when we don't have a minimum coming at us. If we're getting an average of 60 FPS, we should have a minimum of 30 FPS or better and as mentioned above, it means we've got some smooth game play happening.

120 FPS - The new number that we've been hunting down over recent months. If you're the owner of a 120 Hz monitor, to get the most out of it you want to get around the 120 FPS mark. Moving from 60 FPS / 60 Hz to 120 FPS / 120 Hz brings with it a certain fluidity that can't really be explained, but instead has to be experienced. Of course, if you're buying a 120 Hz monitor to take advantage of 3D, an average of 120 FPS in our benchmark means that in 3D you will have an average of 60 FPS, which again means you should expect some smooth gameplay.

Benchmarks - 3DMark 11

3DMark 11

Version and / or Patch Used: 1.1

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3DMark 11 is the latest version of the world's most popular benchmark. Designed to measure your PC's gaming performance 3DMark 11 makes extensive use of all the new features in DirectX 11 including tessellation, compute shaders and multi-threading. Trusted by gamers worldwide to give accurate and unbiased results, 3DMark 11 is the best way to consistently and reliably test DirectX 11 under game-like loads.

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Starting off with 3DMark 11 we can see a nice boost in performance in both our presets. We can also see the gap between the CrossFire and three-way CrossFireX close a bit, but thanks to the excellent optimization present on the three-way setup, it continues to sit a fair bit ahead of all the other setups.

Benchmarks - Unigine Heaven Benchmark

Unigine Heaven Benchmark

Version and / or Patch Used: 2.5

Developer Homepage:

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New benchmark grants the power to unleash the DirectX 11 potential in the gift wrapping of impressively towering graphics capabilities. It reveals the enchanting magic of floating islands with a tiny village hidden in the cloudy skies. With the interactive mode emerging experience of exploring the intricate world is ensured within reach. Through its advanced renderer, Unigine is one of the first to set precedence in showcasing the art assets with tessellation, bringing compelling visual finesse, utilizing the technology to the full extend and exhibiting the possibilities of enriching 3D gaming.

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Just like 3DMark 11, Heaven paints a very nice picture for our overclocked setup as we see a nice boost of over 10% in both resolutions. We continue to find ourselves extremely impressed with what's going on with Tessellation performance on AMD cards.

Benchmarks - Tom Clancy's H.A.W.X. 2

Tom Clancy's H.A.W.X.2

Version and / or Patch Used: Benchmark Demo

Timedemo or Level Used: Built-in Test

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Tom Clancy's H.A.W.X. 2 is an arcade-style flight action game developed by Ubisoft Romania and published by Ubisoft. The game is the sequel to Tom Clancy's H.A.W.X., released in 2009.

The game begins with Colonel David Crenshaw participating in a routine patrol mission in the Middle East. After halting an insurgent attack, a volley of missiles is fired at the Air Force base that Crenshaw was stationed at, with one of the missiles disabling Crenshaw's aircraft, resulting Crenshaw being in enemy captivity. A joint strike force composed of the U.S. Navy, U.S. Air Force, and a Ghost Recon squad executes an operation to rescue Crenshaw. In Scotland, Royal Navy Pilot Colin Munro encounters an unidentified passenger aircraft that explodes from an on-board bomb when undergoing training exercise. In Russia, an air force squadron led by Colonel Denisov and Captain Dmitri Sokov engages separatist aircraft but is ordered to retreat from the region after numerous Russian military installations have been attacked.

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Moving into H.A.W.X. 2 we see a nice boost in performance and we can see because the gains for the three-way setup weren't as strong here the OC CF setup closes those gaps a little.

Looking at the numbers, though, you can see we've just got massive FPS across the board. You're not going to have an issue with smooth gameplay at any resolution with this setup.

Benchmarks - Mafia II

Mafia II

Version and / or Patch Used: Latest Steam Update

Timedemo or Level Used: Built in Benchmark

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Mafia II is a third-person action-adventure video game, the sequel to Mafia: The City of Lost Heaven. It is developed by 2K Czech, previously known as Illusion Softworks, and is published by 2K Games. The game is set from 1943 to 1951 in Empire Bay (the name is a reference to New York's state nickname "The Empire State"), a fictional city based on San Francisco and New York City, with influences from Chicago and Detroit. The game features a completely open-ended game map of 10 square miles. No restrictions are included from the start of the game. There are around 50 vehicles in the game, as well as licensed music from the era.

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Looking at Mafia 2 there's not a whole lot that can be said about performance as we see our CrossFire and CrossFireX setups bounce around that 130 FPS wall that seems to be present.

Benchmarks - Lost Planet 2

Lost Planet 2

Version and / or Patch Used: Benchmark Demo

Timedemo or Level Used: Built in Benchmark - Test A Scene 1

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Lost Planet 2 is a third-person shooter video game developed and published by Capcom. The game is the sequel to Lost Planet: Extreme Condition which is also made by Capcom, taking place ten years after the events of the first game, on the same fictional planet. The story takes place back on E.D.N. III 10 years after the events of the first game. The snow has melted to reveal jungles and more tropical areas that have taken the place of more frozen regions. The plot begins with Mercenaries fighting against Jungle Pirates. After destroying a mine, the Mercenaries continue on to evacuate the area, in which a Category-G Akrid appears and attacks them. After being rescued, they find out their evacuation point (Where the Category-G appeared) was a set-up and no pick up team awaited them. The last words imply possible DLC additions to the game, "There's nothing to be gained by wiping out snow pirates... unless you had some kind of grudge."

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Moving into something quite intensive we can see some nice gains under Lost Planet 2 at all resolutions.

I didn't think we'd be seeing averages of almost 150 FPS at 2560 x 1600 with dual GPU setups any time soon, but the new HD 7970 is such a beast of a GPU under these Tessellation heavy engines.

Benchmarks - Aliens vs. Predator

Aliens vs. Predator

Version and / or Patch Used: Standalone Benchmark

Timedemo or Level Used: Built in Benchmark

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Aliens vs. Predator is a science fiction first-person shooter video game, developed by Rebellion Developments, the team behind the 1999 original PC game, and published by Sega for Microsoft Windows, the PlayStation 3 and the Xbox 360. The game is based on the Alien vs. Predator franchise, a combination of the characters and creatures of the Alien franchise and the Predator franchise. There are three campaigns in the game, one for each race/faction (the Predators, the Aliens and the Colonial Marines), that, while separate in terms of individual plot and gameplay, form one overarching storyline.

Following the storyline of the campaign modes comes the multiplayer aspect of the game. In this Multiplayer section of the game, players face off in various different gametypes in various different ways.

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Checking out another intensive game in the forms of Aliens vs. Predator we continue to see a nice boost across the board thanks to the overclock on offer. For the most part we're seeing gains that sit around the 10% mark.

Benchmarks - Just Cause 2

Just Cause 2

Version and / or Patch Used:

Timedemo or Level Used: Dark Tower

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Just Cause 2 employs the Avalanche Engine 2.0, an updated version of the engine used in Just Cause. The game is set on the other side of the world from the original Just Cause, on the fictional island of Panau in Southeast Asia. Panau has varied terrain, from desert to alpine to rainforest. Rico Rodriguez returns as the protagonist, aiming to overthrow the evil dictator Pandak "Baby" Panay and confront his former mentor, Tom Sheldon.

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Like we've been seeing all along, Just Cause 2 sees another nice boost in performance at all resolutions. The biggest surprise in performance continues to come from comparing the HD 7970 CF setup against the older HD 6990 dual GPU card.

It gets us really excited about what the forthcoming AMD Radeon HD 7990 is going to bring to the table when it hits the market later.

Benchmarks - Metro 2033

Metro 2033

Version and / or Patch Used: Latest Steam Update

Timedemo or Level Used: Built in Benchmark

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Metro 2033 is an action-oriented video game with a combination of survival horror and first-person shooter elements. The game is based on the novel Metro 2033 by Russian author Dmitry Glukhovsky. It was developed by 4A Games in Ukraine and released in March 2010 for Microsoft Windows and Xbox 360.[3] In March 2006, 4A Games announced a partnership with Glukhovsky to collaborate on the game.[4] The game was announced at the 2009 Games Convention in Leipzig;[5] a first trailer came along with the announcement.[6] A sequel was announced, currently titled Metro: Last Light.

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Metro 2033 is a bit of a weird title. As intensive as it is, we seem to hit a bit of a wall with it. When overclocking, like with the introduction of a third card, brings a slight boost to 2560 x 1600 performance, but aside from that, there's not much else to get excited about.

The good news is we've got awesome FPS across the board and that's all that really matters in the end.

Benchmarks - Dirt 3

Dirt 3

Version and / or Patch Used: Latest Steam Update

Timedemo or Level Used: Built in Benchmark

Developer Homepage:

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DiRT 3 boasts more cars, more locations, more routes and more events than any other game in the series, including over 50 rally cars representing the very best from five decades of the sport. With more than double the track content of 2009's hit, DiRT 3 will see players start at the top as a professional driver, with a top-flight career in competitive off-road racing complimented by the opportunity to express themselves in Gymkhana-style showpiece driving events.

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Checking out Dirt 3 performance we can see some nice performance gains across the board making sure that game play will continue to be silky smooth at every resolution you throw at this setup.

Benchmarks - Far Cry 2

Far Cry 2

Version and / or Patch Used: 1.01

Timedemo or Level Used: Ranch Long

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The Dunia Engine was built specifically for Far Cry 2 by the award-winning Ubisoft Montreal development team. It delivers the most realistic destructible environments, amazing special effects such as dynamic fire propagation and storm effects, real-time night-and-day cycle, dynamic music system, non-scripted enemy A.I. and so much more.

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Looking at FarCry 2 numbers you can see our CrossFire setup hits that 150 / 290 FPS wall which means overclocking does little to performance.

We should get a better idea of what overclocking does for FarCry 2 when we look at our AA / AF tests on the next page.

Benchmarks - High Quality AA and AF

High Quality AA and AF

Our high quality tests let us separate the men from the boys and the ladies from the girls. If the cards weren't struggling before they will start to now.

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While we don't see much change in Mafia 2 numbers, when we look at Aliens vs. Predator and FarCry 2 numbers, we see a nice little boost in performance and that's always appreciated under these highly intensive situations.

Temperature Test

Temperature Tests

The temperature of the core is pulled from MSI Afterburner with the max reading used after a completed run off 3DMark Vantage and the Performance preset.

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Checking out the heat numbers we can see that our hottest card manages to run a fair bit warmer coming in line with the three-way CrossFireX setup. This is of course no doubt due to the fact we're dealing with extra voltage on the core of the cards.

What does look a bit more attractive is the idle number which sits significantly lower than the three-way setup. That's of course due to the fact that we still have a nice gap between the video cards thanks to the ASUS Rampage IV Extreme motherboard layout.

Sound Test

Sound Tests

Pulling out the TES 1350A Sound Level Meter we find ourselves quickly yelling into the top of it to see how loud we can be.

After five minutes of that we get a bit more serious and place the device two CM away from the fan on the card to find the maximum noise level of the card when idle (2D mode) and in load (3D mode).

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Getting into the noise side of things we can see a bump in both idle and load numbers. Noise levels here are clearly more audible, but we continue to see the setup come in a little quieter than the HD 6990 which was always known to be an extremely loud card.

Power Consumption Tests

Using our new PROVA Power Analyzer WM-01 or "Power Thingy" as it has become quickly known as to our readers, we are now able to find out what kind of power is being used by our test system and the associated graphics cards installed. Keep in mind; it tests the complete system (minus LCD monitor, which is plugged directly into AC wall socket).

There are a few important notes to remember though; while our maximum power is taken in 3DMark06 at the same exact point, we have seen in particular tests the power being drawn as much as 10% more. We test at the exact same stage every time; therefore tests should be very consistent and accurate.

The other thing to remember is that our test system is bare minimum - only a SSD hard drive is used with a single CD ROM and minimal cooling fans.

So while the system might draw 400 watts in our test system, placing it into your own PC with a number of other items, the draw is going to be higher.

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Power Draw sky rockets when overclocked and you can see the overclocked CrossFire setup actually draws more power than the three-way CrossFireX setup when running at stock.

The biggest surprise comes in the form of the idle number that jumps. To overclock in CrossFire you need to disable Ultra Low Power State which means we see a big jump in power draw when running at idle.

Final Thoughts

I didn't think I'd say this, but I wouldn't bother overclocking the new AMD Radeon HD 7970 when running in CrossFire mode. It's not because of the performance gains, you can see across the board that there's some nice gains, but when you start to look at it all, the overclock doesn't move us from an unplayable setup to a playable one. Instead you look across the board and the HD 7970 in CrossFire is just offering us very playable numbers across the board at any resolution without being overclocked.

The numbers that really turn us off when it comes to overclocking comes in the form of the last three graphs. When it comes to the temperature we see a jump in both idle and load numbers. Moving over to noise levels also sees a jump and it's a clear one when it comes to the load numbers.

Finally that leaves us with the power numbers; while I've never been one to really care about the power numbers, the Ultra Low Power State that's present on these cards is awesome at idle and overclocking brings in another 100 watt of power draw when doing the exact same thing.

Reference coolers tend to be the best when it comes to CrossFire setups because of the way they push the air out. With the large gap we get between cards on the ASUS Rampage IV Extreme motherboard, though, I think that some aftermarket options in the form of VaporX from Sapphire, IceQ from HIS and TwinFrozr from MSI will yield better results. Not just in the form of heat and noise numbers, but being more efficient when it comes to cooling should help yield a stronger overclock.

If you're going to do a bit of benchmarking, muck around on some forums in a 3DMark 11 ranking thread, then I'd say have a bit of fun overclocking. In those situations I'd suggest you even crank the fan speeds up to 100%. While unbearable, the added airflow will help yield more performance in terms of overclocking.

For an everyday setup, I wouldn't bother too much as the trade off in power, heat and noise out weight any real benefits overclocking brings. You'd be better of picking up a pair of pre-overclocked video cards that came in at around the 1000MHz core mark.

As always, overclocking is a heap of fun, the amount of power these cards put out running at stock, though, mean that everyday overclocking probably isn't quite as exciting as other video cards. It's going to be interesting to see what happens with the models that will sit below, though. HD 7950 CrossFire overclocking is going to be interesting and we hope that we'll be able to close the gap between a stock HD 7950 CF setup and a HD 7970 CF setup.

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Shawn takes care of all of our video card reviews. From 2009, Shawn is also taking care of our memory reviews, and from May 2011, Shawn also takes care of our CPU, chipset and motherboard reviews. As of December 2011, Shawn is based out of Taipei, Taiwan.

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