Sapphire Radeon HD 6990 Review
Reviewed by: ccokeman
Reviewed on: March 13, 2011
Back in November when AMD brought OCC out to LA for the 6 series launch event, the HD 6990 Antilles was not much more than a footnote in the presentation as an all new "Future Product". A product we were told not to talk about as it was under NDA with more information to be forthcoming. Here we are a few months later with that product ready for review. Today we have the Sapphire HD 6990. AMD has held onto the single card performance title since the introduction of the HD 5970 while NVIDIA steadily chipped away at that lead as they refined their Fermi architecture to the point of delivering a card (in the form of the GTX 580) that took back the single GPU card title that AMD had hoped to capture with the HD 6970. Being just "good enough" is no longer acceptable and with this launch AMD has pushed the envelope in terms of the thermals and power consumption to make the HD 6990 a point of difference and deliver game changing performance much the same way the HD 4870x2 and HD 5970 did.
Under the hood, the HD 6990 is nothing more than a pair of HD 6970 Cayman GPU cores that have been binned for low leakage ASICs and downclocked to meet the temperature and power commitments of the card's design. The HD5970 was built to fit into a 300 watt profile while the HD 6990 is designed to fit into a 375 watt profile with the ability to bump up to 450 watts via the AUSUM switch. This switch (used on all HD 69XX series cards) now gets a new function as an overclocking switch that loads a new voltage and clock speed profile. Something the HD 5970 lacked. This one change bumps the core clock speed and voltage up to meet HD 6970 clock speeds of 880MHz from the standard, as delivered HD 6990 clock speed of 830MHz. More changes that include refining the cooling design and voltage circuits promises a new take on the dual GPU, single PCB, video card. Let's take a look at what AMD and Sapphire now have to offer with their upper crust HD 6990.
The packaging for the Sapphire HD 6990 is traditional Sapphire. Up front, the inclusion of a second rendition of Ruby is a clue that you have a pair of something special inside the package. Much the way the last few dual GPU cards from Sapphire I have looked at have been portrayed. Once the eyes are averted from the beauties on the front, you can get to business looking into the merits of the extensive feature set listed on the front panel that include 4GB of GDDR5 memory, dual graphics engines, AMD HD3D, 7.1 HD surround sound, Display Port 1.2 and AMD Eyefinity multi-monitor display technology. On the back panel the product highlights are discusssed as well as a listing of the contents of the package. On the right hand side, a brief synopsis is given about the supported technologies.
Inside the outer sleeve is a plain box by comparison that holds the Sapphire HD 6990 and the bundled accessories. The top formed tray holds the card in an antistatic bag while the lower tray holds the substantial accessory bundle.
The bundle of accessories for this card includes all of the adapters needed to hook the card up to an Eyefinity setup and includes the driver disk with a Sapphire sticker for your case, a quick start guide, CrossFire™ Bridge Interconnect Cable, DVI to VGA Adapter, Mini-DP to DP Cable, Mini Display Port to HDMI dongle, Mini DP to SL-DVI Passive dongle and a Mini Display Port to SL-DVI Active dongle. All of the attached cables would easily set you back a few bucks if not included.
The HD 6990 promises huge performance but before we get down to testing let's take a good look at the Sapphire HD 6990.
Much like the HD 5970, the HD 6990 uses two GPU cores attached to a single PCB to deliver on the "King of the Hill" performance target that AMD is aiming for. Two Cayman XT GPU cores power this beast code named "Antilles" using the same architecture as the HD 6970. The Sapphire HD 6990 is a dual slot card much like the rest of the HD 6XXX and 5XXX family of GPUs from AMD. It should be no surprise that with the amount of hardware on board, this card is a full 12 inches in length, the same as the last generation HD 5970. For basic specs there are a total of 3072 Stream Processors clocked at 830/880MHz depending on whether or not you use the AUSUM switch feature, 192 Texture units, 64 ROPs and a massive 4GB of GDDR5 memory running through a 2 x 256bit bus. The GDDR5 memory is clocked at 1250MHz. What does all this add up to in terms of performance? If you can hold on a few seconds more, we're going to find out. The front side of the card has a decal from Sapphire but other than that, the card looks the same as a reference card. The front side of the card is dominated by the centrally located radial fan replacing the blower style fan used on past designs. The back side of the card has a back plate that is used to both stiffen the card and work as a heat sink for the eight memory modules on the back side of the PCB.
Connectivity options have changed since the HD 5970 with the HD 6990 coming with a single Dual Link DVI port and a total of four Mini Display Port 1.2 ports. This configuration is optimized for use with an Eyefinity setup with up to five monitors right now with the current technology. To get a full six monitors, you will need to use DisplayPort 1.2 equipped monitors that support daisy chaining or a not yet available Multi Stream Transport hub. With the change in connectivity, the card now has more room to breath and exhaust the heat from the front GPU heat sink. The rear of the card is open to allow the airflow from the rear heat sink to exhaust out from under the shroud only this time, that thermal load will be dumped into your case. This means that not only do you need a large chassis to install this card in you need one that has quite a bit of airflow to quickly exchange the air in the chassis as it heats up. Curious as to the temperatures coming out of the front and rear exhaust ports on the HD 6990 I pulled out my handy Kestral Airflow tracker and used its temperature monitoring capabilities to measure the temperature of the airstream. The front port sent air out at 44 degrees Celsius while the rear was similar at 41C. Don't put an HDD behind the card or it may just get the heat treatment.
The little yellow sticker that is strategically placed over the BIOS recovery switch implores you to read the manual before removing the sticker. On the HD 6970 and HD 6950 this switch is nothing more than a means to recover the VGA BIOS if it is somehow corrupted. Enterprising enthusiasts have done what we do when presented with an opportunity and figured out that an HD 6970 BIOS could be flashed to the HD 6950 to unlock the cores and deliver HD 6970 performance for the cost of an HD 6950. PowerColor has gotten in the game already and produced a card with the appropriate BIOSes already flashed. On the HD 6990, this switch is called the AUSUM (Antilles Unlocking Switch for Uber Mode) dual BIOS switch - and who says manufacturers don't have a sense of humor! This switch bumps up the GPU core voltage and clock speeds to 1.175v and 880MHz from 1.125v and 830MHz. The first position supports factory clocks and voltages while the second position is for the overclocking enthusiast. The decal is a clue that moving the switch to the higher clocks and voltages is not supported by any warranty. The statement in the press deck from AMD reads " AMD’s product warranty does not cover damages caused by overclocking,even when overclocking is enabled via AMD software and/or the Dual-BIOS Function on the AMD Radeon™ HD 6990". Kind of makes you wish they made us work for it rather than putting it there, daring us to use it. The switch is slightly recessed so the AUSUM mode cannot be accidentally enabled and subsequently voiding your warranty.
The Sapphire HD 6990 supports Quad CrossfireX with one other HD 6990 and most likely three way CrossfireX by adding an HD 6970 to the mix. The power profile of this card dictates that it is connected to dual 8 pin PCIe power connections to supply a total of 375 watts of power to the card. The HD 6990 is capable of using up to 450 watts using AMD's Power Tune technology when the AUSUM switch is pushed over to the hardware overclocking mode so a large enthusiast style power supply is going to be a requirement not an option.
AMD suggests that the card not be taken apart due to the Phase Change TIM that sets and creates a bond with heat to deliver an 8% improvement in thermal performance. Suggestions are just that so apart it came. The backplate is metal and acts as a passive heat sink for the memory modules on the back of the PCB. Pulling the HD 6990 apart requires pulling the back plate and heat sink brackets then gently prying the card apart. A little heat from a hair dryer helps by warming up the TIM to gain some separation. Then to get into the heat sink plate on the front of the card requires a series of screws to be removed. Underneath is the centrally located radial fan mounted on the finned aluminum plate. The HD 6990 differs from the HD 5970 tremendously here as there are two Vapor Chamber equipped heat sinks on opposite sides of the fan instead of a single large assembly as used on the HD 5970. The TIM indeed had hardened up due to my testing but was not as difficult to remove as some of the TIM applications I have seen over the past year.
One of the major flaws with the HD 5970 was that it was susceptible to throttling when the VRM circuit was overheated. In some cases running at stock speeds. To eliminate that as a concern, AMD have put the next generation digital programmable Volterra regulators in the center of the PCB to feed each core and its associated memory. These new devices are said to be more efficient, run cooler and have a higher current capacity than the previous design. THE PLX Bridge chip looks to be the same one used on the AMD HD 5970 and is again carrying the AMD logo on it.
The Cayman XT cores are built on a 40nm process at TSMC with 2.64 Billion transistors all in a die sized at 389mm2. The two cores are equipped with a total of 3072 stream processors, 192 texture units, 64 color ROPS and 256 Z/Stencil ROPs. The core is clocked at 830MHz as delivered from the manufacturer but can be bumped up to 880MHz with the AUSUM switch to deliver a higher level of performance. The GDDR5 memory used on this HD 6990 from Sapphire is made by Hynix and is rated for operation at 1250MHz and runs through a 2 x 356 bit bus. While these are the base specifications, they all add up to a significant increase in compute performance and deliver between 5.1 and 5.40 TFLOPS of compute performance with the memory delivering 320Gb/s of bandwidth.
On paper the HD 6990 looks like a killer card that should easily topple the HD 5970 from its perch as the fastest single video card.
- Dual GPU Design
- Dual BIOS to switch between Performance mode and Extreme Performance mode
- Up to 880 MHz Engine Clock
- Effective 5.0 GHz Memory Clock
- 2x 1536 Stream Processors
- 2x 256 bit GDDR5 Memory Interface
- Microsoft DirectX 11 Support
- AMD Eyefinity Technology
- AMD Power Tune Technology—dynamically optimized performance
- Open GL 4.1 Support
- AMD HD3D Technology
- AMD Advanced Parallel Processing Technology
- Microsoft Windows 7 Support
- 40nm Process Technology
- 4th Generation TeraScale Engine
- PCI Express 2.1 x16 bus interface
- HDMI 1.4a support with Deep Color, 7.1 High Bitrate Audio and 3D Stereoscopic support
- Display Port 1.2
- ATI CrossFireX™ multi-GPU support
- Enhanced Unified Video Decoder(UVD 3)
- Dynamic power management with ATI PowerPlay™ technology including memory clocks
- Dolby® TrueHD and DTSHD Master Audio TM Support
- Enhanced Internet Brower Applications
- GPU acceleration support for Microsoft Office 2010
All information courtesy of Sapphire Tech and AMD @ http://www.sapphiretech.com/presentation/?lid=1
Testing of the Sapphire Radeon HD 6990 will consist of running it and comparison cards through the OverclockersClub.com suite of games and synthetic benchmarks. This will test the performance against many popular competitors. Comparisons will be made to cards of equal and greater capabilities to show where they fall on the performance ladder. The games used are some of today's newest and most popular titles to give you an idea of how the cards perform relative to each other.
The system specifications will remain the same throughout the testing. No adjustment will be made to the respective control panels during the testing, with the exception of the 3DMark Vantage testing, where PhysX will be disabled in the NVIDIA control panel. I will test the cards at stock speeds, then overclocked in order to see the effects of any increases in clock speed. The cards are placed in order from highest to lowest performing in the graphs to show where the cards fall by comparison.
- Processor: Intel Core I7 920 200x18 3.6GHz
- Cooling: Noctua NH-U12P SE 1366
- Motherboard: ASUS P6T Deluxe OC Palm Edition
- Memory: Mushkin 996805 Redline PC312800 6-8-6-24 1600MHz
- Video Card: Sapphire HD 6990
- Power Supply: Mushkin 1000 watt Joule Modular power supply
- Hard Drive: 1 x Seagate 1TB SATA
- Optical Drive: LG DVD-RW
- OS: Windows 7 Professional 64-bit
- Case: Cooler Master HAF 932
Comparison Video Cards:
- EVGA GTX 460 FTW
- ASUS ENGTX465
- NVIDIA GTX 480
- Galaxy GTX 470 GC
- Sapphire HD 5970 2GB
- Sapphire HD 5870
- Sapphire HD 5850 Toxic 2GB
- XFX HD 6850
- XFX HD 6870
- NVIDIA GTX 580
- NVIDIA GTX 570
- HD 6970 & HD 6950
- HD 6970 CrossfireX
- ASUS GTX 570 SLI
- ASUS GTX 580 SLI
- Sapphire HD 6990 940MHz 1473MHz
Overclocking on the HD 6990 is a simple as flicking a switch. Although you may not like the ramifications of flipping this switch if the card goes belly up as one of my GTX 570s did after a quick batch of testing for this article. By using the AUSUM switch on the spine of the card you can take the card from its default 830MHz clocks to the overdriven 880MHz at 1.175v. AMD gives the enthusiast/overclocker the ability to see a speed bump with nothing more than flicking a switch. Truth be told it works and shows a slight FPS increase when you need it. On the other hand we have the way we normally do things and used a combination of tools including Sapphire's TRIXX utility to bump the clocks up. The core was bumped up to an aggressive 950MHz to start with and was a bit to much for the card and voltage capabilities of 1.175v. Reducing the clock speed to 940Mhz was met with success and is the final clock speed I was able to achieve. This is an increase of 110MHz over the 830Mhz base speed on the cores. The GDDR5 memory scaled quite well and was able to reach a lofty 1473MHz before causing issues in the gaming tests. 1500Mhz was my target as the 6970 seems to reach these speeds at will but a 223MHz improvement is well worth the effort. To reach these speeds I left the AUSUM switch in the overclocked mode and bumped up the fan speed to 80% as that's all I could really stand for the duration of my testing. AMD just cannot get the airflow vs. noise problem solved on its last few releases and seem to be taking steps backwards. Bumping up the fan has advantages but the noise penalty may not be worth the improved cooling.
Maximum Clock Speeds:
In the past, I had used MSI's Kombuster utility to check for stability coupled with the ability to run through the entire test suite. I have found that some game tests would still fail with this utility, so I have moved to testing with several games at maximum settings through several resolutions to verify the clock speeds that are listed below. Why the change? I have found some cards will play fine at a 4xAA setting, but fail when using 8xAA due to the increased graphics load. If it fails, then the clock speeds and tests are rerun until they pass.
- Gaming Tests:
- Aliens vs. Predator
- Metro 2033
- Crysis Warhead
- Call of Duty: Modern Warfare 2
- Just Cause 2
- Unigine Heaven Benchmark 2.1
- Batman: Arkham Asylum
- Battlefield: Bad Company 2
- 3DMark 11
- 3DMark Vantage
- Power Consumption
Aliens vs. Predator, developed by Rebellion Developments, is a science fiction first-person shooter and is a remake of its 1999 game. The game is based off the two popular sci fi franchises. In this game, you have the option of playing through the single player campaigns as one of three species, the Alien, the Predator, and the Human Colonial Marine. The Game uses Rebellion's Asura game engine that supports Dynamic Lighting, Shader Model 3.0, Soft Particle systems, and Physics. To test this game I will be using the Aliens vs. Predator benchmark tool with the settings listed below. All DirectX 11 features are enabled.
- SSAO = On
- Texture Quality = Very High
- Hardware Tesselation = On
- Advanced Shadow Sampling = On
Higher = Better
In this first test, there is no doubt that AMD hit the mark with the HD 6990, and in this game it is the fastest single video card solution right now. When compared with the HD 6970 Crossfire and SLI solutions it performs almost identically to the HD 6970 Xfire, and sits right between the GTX 580 and GTX 570 SLI solutions.
Part first-person shooter, part survival horror, Metro 2033 is based on the novel of the same name, written by Russian author Dmitry Glukhovsky. You play as Artyom in a post-apocalyptic Moscow, where you'll spend most of your time traversing the metro system, with occasional trips to the surface. Despite the dark atmosphere and bleak future for mankind, the visuals are anything but bleak. Powered by the 4A Engine, with support for DirectX 11, NVIDIA PhysX and NVIDIA 3D Vision, the tunnels are extremely varied — in your travels, you'll come across human outposts, bandit settlements, and even half-eaten corpses. Ensuring you feel all the tension, there is no map and no health meter. Get lost without enough gas mask filters and adrenaline shots and you may soon wind up as one of those half-eaten corpses — chewed up by some horrifying manner of irradiated beast that hides in the shadows just waiting for some hapless soul to wander by.
- DirectX 11
- Global settings = High
- Physx = off
Higher = Better
In Metro 2033 at stock speed testing the Sapphire HD 6990 falls behind the HD 6970 Crossfire and two SLI solutions in all three resolutions. When overclocked it is faster than the pair of HD 6970's in all three resolutions. The HD 6990 is easily faster than the highest performing single card solution - the GTX 580. But when two GTX 580's are paired together, the HD 6990 is the slower performer.
Crysis Warhead is a standalone expansion pack situated in time with the story line of the original Crysis. As Sergeant "Psycho" Sykes, you have a secret mission to accomplish on the far side of the island. Along the way there are EMP blasts and aliens to contend with, as you hunt down the KPA chief. This game uses an enhanced version of the CryEngine 2.
- Frost Map
- DirectX 10
Higher = Better
The HD 6990 and HD 6970 Crossfire setup are the two fastest solutions in Crysis Warhead with the highest level of performance. Again easily beating the GTX 580 single card solution.
Call of Duty: Modern Warfare 2 is an iteration of the venerable first person shooter series, Call of Duty. Despite its long, successful pedigree, the game is not without substantial criticism and controversy, especially on the PC. Aside from the extremely short campaign and lack of innovation, the PC version's reception was also marred by its lack of support for user-run dedicated servers, which means no user-created maps, no mods, and no customized game modes. You're also limited to 18-player matches instead of the 64-player matches that were possible in Call of Duty 4: Modern Warfare. Despite all this, the game has been well received and the in-house IW 4.0 engine renders the maps in gorgeous detail, making it a perfect candidate for OCC benchmarking. You start off the single player missions playing as Private Allen and jump right into a serious firefight. This is the point where testing will begin. Testing will be done using actual game play with FPS measured by Fraps.
- In-game settings to Maximum
- Fraps measured Gameplay
Higher = Better
Again we see the HD 6990 outperforming the last generation HD 5970 and GTX 580 by substantial margins. The HD 6970 Crossfire setup is more efficient at the lower resolutions and out performs the HD 6990 while at 2560x1600 the HD 6990 outperforms the dual card setup. Both NVIDIA SLI configurations have strong showings taking the top spots in all tests in this game except stock speeds at 2560 x 1600.
Just Cause 2 is a third-person shooter that takes place on the fictional island of Panau in Southeast Asia. In this sequel to 2006's Just Cause, you return as Agent Rico Rodriguez to overthrow an evil dictator and confront your former boss. When you don't feel like following the main story line, you're free to roam the island, pulling off crazy stunts and causing massive destruction in your wake, all beautifully rendered by the Avalanche Engine 2.0. In the end, that's what the game basically boils down to — crazy stunts and blowing things up. In fact, blowing things up and wreaking havoc is actually necessary to unlock new missions and items.
- Global Settings = High
- Water Detail = Medium
- Dark Tower Time Demo
Higher = Better
The HD 6990 is again the fastest single card in this game. When compared against multi-GPU solutions, the pair of 6970s is slightly faster in most of the resolutions. The GTX 570 SLI solution does very well against the 6990 in all six resolutions.
Unigine Heaven Benchmark 2.1 is a DirectX 11 GPU benchmark based on the Unigine engine. What sets the Heaven Benchmark apart is the addition of hardware tessellation, available in three modes — Moderate, Normal and Extreme. Although tessellation requires a video card with DirectX 11 support and Windows Vista/7, the Heaven Benchmark also supports DirectX 9, DirectX 10 and OpenGL. Visually, it features beautiful floating islands that contain a tiny village and extremely detailed architecture.
- Shaders = High
- Tesselation = Normal
- Measurement = FPS
Higher = Better
In the Heaven Benchmark the HD 6990 easily outperforms the HD 5970 and GTX 580. When compared to the HD 6970 Crossfire setup the results were up and down against it.
Batman: Arkham Asylum is a new game that brings together two bitter rivals, the Joker and Batman. The Joker has taken over Arkham Asylum, Gotham's home for the criminally insane. Your task is to rein the Joker back in and restore order. This game makes use of PhysX technology to create a rich environment for you to become the Dark Knight.
- 4xAA in CP
- 16xAF in CP
- Global settings = High
- Ambient Occlusion = On
Higher = Better
At stock speeds the HD 6990 is slower than the 6970 Crossfire combo yet when overclocked they are almost equal due to the similar clock speeds. As the resolution increases the performance margin over the GTX 580 grows. As you can see the SLI solutions do very well and are in a league of their own.
Battlefield: Bad Company 2 is a first-person shooter developed by EA Digital Illusions CE (DICE) and published by Electronic Arts for Windows, PS3 and XBox. This game is part of the Battlefield franchise and uses the Frostbite 1.5 Engine, allowing for destructible environments. You can play the single player campaign or multiplayer with five different game modes. Released in March 2010, it has so far sold in excess of six million copies.
- Global settings = Advanced
- HBAO = Off
Higher = Better
Even though it is the fastest single card, the performance differential is not as great in this game as it has been in others.
3DMark 11 is the next installment for Futuremark in the 3DMark series with Vantage as its predecessor. The name implies that this benchmark is for Microsoft DirectX 11 and with an unintended coincidence, the name matches the upcoming date in number (which was the naming scheme to some prior versions of 3DMark nonetheless). 3DMark 11 is designed solely for DirectX 11 so Windows Vista or 7 are required along with a DirectX 11 graphics card in order to run this test. The Basic Edition has unlimited free tests on performance mode whereas Vantage only allowed for a single test run. The advanced edition costs $19.95 and unlocks nearly all of the features of the benchmark and the professional edition runs $995.00 and is mainly suited for corporate use. The new benchmark contains six tests, four of which are aimed only at graphical testing, one to test for physics handling and one to combine graphics and physics testing together. The open source Bullet Physics library is used for physics simulations and although not as mainstream as Havok or PhysX, it still seems to be a popular choice.
With the new benchmark comes two new demos that can be watched, both based on the tests but unlike the tests, these contain basic audio. The first demo is titled "Deep Sea" and have a few vessels exploring what looks to be a sunken U-Boat. The second demo is titled "High Temple" and is similar to South American tribal ruins with statues and the occasional vehicle around. The demos are simple in that they have no story, they are really just a demonstration of what the testing will be like. The vehicles have the logos of the sponsors MSI and Antec on their sides with the sponsorships helping to make the basic edition free. The four graphics tests are slight variants of the demos. I will use the three benchmark test preset levels to test the performance of each card. The presets are used as they are comparable to what can be run with the free version so that results can be compared across more than just a custom set of test parameters.
- Default test settings
- Entry test 1024 x 600
- Performance test 1280 x 720
- Extreme test 1920 x 1080
Higher = Better
The HD 6990 delivers the highest single card performance in this benchmark but is in the middle of the pack when compared to the multi-card solutions.
Featuring all-new game tests, this benchmark is for use with Vista-based systems. "There are two all-new CPU tests that have been designed around a new 'Physics and Artificial Intelligence-related computation.' CPU test two offers support for physics related hardware." There are four preset levels that correspond to specific resolutions. "Entry" is 1024 x 768 progressing to "Extreme" at 1920 x 1200. Of course, each preset can be modified to arrange any number of user designed testing. For our testing, I will use the four presets at all default settings.
- Settings (each preset): Default Testing
- Entry: 1024 x 768
- Performance: 1280 x 1024
- High: 1680 x 1050
- Extreme: 1920 x 1200
Higher = Better
At stock speeds the HD 6990 delivers a higher level of performance at the lower resolutions while in the upper resolutions the higher clock speeds of the pair of 6970s perform better. Again you can see the SLI configurations doing very well, holding the top spots except for one resolution where the 570's finish in third spot.
Temperature testing will be accomplished by loading the video card to 100% using MSI Kombuster, which is paired with MSI's Afterburner overclocking utility for temperature monitoring. I will be using the stability test set to a resolution of 1920x1200 using 8xAA. I will use a 15 minute time frame to run the test, ensuring that the maximum thermal threshold is reached. The fan speed will be left in the control of the driver package and video card's BIOS for the stock load test, with the fan moved to 100% to see the best possible cooling scenario for the overclocked load test. The idle test will be a 20 minute cool down with the fan speeds left on automatic in the stock speed testing and bumped up to 100% when running the overclocked idle and load testing. For load testing the GTX 580 and GTX 570, I will use Crysis Warhead run at 2560x1600 using the Gamer setting with 8xAA looping the Avalanche benchmark scenario, as I have found this to put a load close to that of Kombuster on a video card. This is needed as a way around the current limiting ability of the GTX 500 series when it detects programs that put an unrealistic load on the GPU, which Kombuster does.
- Monitoring with MSI Afterburner
- GPU Stability test in MSI Kombuster
- 15 minute load duration
- 20 minute idle duration
- Temperature measured in degrees Celsius
Lower = Better
The temperatures delivered by the HD 6990 are respectable and mirror the HD 5970 in all the testing save the overclocked testing where the HD 6990 is 15 degrees cooler based on the new cooling design. The only problem is that the solution is incredibly loud when pushed to the upper limits of the fan speed. The other down side is that 50% of the air flows out into the chassis. This in turn will raise the temperatures of the components in the chassis if the airflow through the chassis is not sufficient to remove the heat.
Power Consumption of the system will be measured in both idle states and loaded states and will take into account the peak voltage of the system with each video card installed. I will use MSI Kombuster to load the GPU for a 15 minute test and use the peak load of the system as my result for the maximum load. The idle results will be measured after 15 minutes of inactivity on the system. For load testing the GTX 500 series, I will once again use Crysis Warhead run at 2560 x 1600 using the Gamer setting with 8xAA looping the Avalanche benchmark scenario.
- MSI Kombuster Stability test
- 1920 x 1200 Resolution
- 15 minute load test
- 15 minute idle test
- Measurement is in Watts
Lower = Better
At stock speeds, the HD 6990 delivers lower idle power consumption than the HD 5970 but under load it is slightly higher. The opposite is true when overclocked. When compared to the pair of HD 6970's in Crossfire, the HD 6990 is more efficient. Even so, the person in the market for this style of card is not going to be to concerned with the power consumption numbers but the raw performance delivered. Most people will likely have either multiple monitors or a large single display to run 2560 x 1600 or 5760 x 1080.
Is the HD 6990 the master of its domain? Why yes...yes it is. Much like when the HD 5970 was launched, the HD 6990 just cleans up and delivers FPS numbers that can't be matched by any single video card currently out today. In that respect it is a winning proposition for AMD as they rightly retain the single card performance crown. When overclocked, it moves one step further up the performance ladder with game changing performance. Metro 2033 and AVP are now playable at 2560 x 1600 with the eye candy and all of the DX 11 feature set enabled. This puts the card in a position to be able to handle the next generation of games coming out over this coming year (Crysis 2 anybody?). If it turns out that it can't handle the latest games you can always manually bump the clock speeds up for that additional boost you need. The Sapphire HD 6990 is a reference card so I am confident that just about any of the HD 6990 cards out there can reach the speeds I was able to reach of 940/1473MHz. I did this by flipping the AUSUM switch to the overclock mode to get the small bump in core clock voltage and adjusting the clock speed up and fan speeds to 80% to keep the card cooler. These clock speeds represent increases of 110MHz on the core and 223MHz on the GDDR5 memory. Now a couple things that concerned me.
One being the AUSUM switch that is put on there to allow the enthusiast to take advantage of higher clock speeds and performance but they put a little sticker on it saying if you move the switch you're going to have to do without any warranty support. If the concern is that great then the switch should have been there only for its intended purpose as a BIOS recovery option. Second is the noise that this card produces when the fan speed is ramped up. Start up that shop vac and you have an idea of what that 5000RPM capable fan can do. I will admit that when the fan is ramped up the temperature profile is better than that of the HD 5970. At stock speeds the temperature profile is spot on with the HD 5970 so you get much improved performance with the same thermals. The only down side to the dual heat sink design is that half the hot air is dumped into the chassis raising the internal temperatures of the case's components. A case with excellent airflow should be mandatory with this card.
When you compare the performance delivered to what you get with a pair of HD 6970's, the pricing structure does not really add up. A pair of HD 6970s clocked at 880/1250MHz will set you back about $680 or less depending on rebates. The HD 6990 is available for $710 and up and delivers slightly lower performance in most cases. The GTX 570's in SLI deliver performance that is up and down against the HD 6990 for the same cost commitment as the pair of HD 6970's so you have some value concerns there. However, at this time, the HD 6990 does something no current generation single card from NVIDIA can do, run a surround (Eyefinity) setup. Will that change with NVIDIA's rumored upcoming dual GPU card? Time will tell. At this point if you have to have the fastest single card on the planet then the Sapphire HD 6990 is going to be it. You get game changing performance and a host of features that allow this card to meet all of your gaming needs, built in one touch overclocking and a card that just blows the competition away.
- Fastest Single Card Available Today
- Eyefinity 5 Portrait Mode
- Game Changing Performance
- AUSUM Switch Voids Warranty
- Hot air Dumped into the Case