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AMD Radeon HD 6990 Review: Antilles Has Arrived
Date: Mar 08, 2011
Author: Marco Chiappetta
Introduction and Specifications

The product we’ll be featuring here today, the AMD Radeon HD 6990, should come as no surprise to anyone that even remotely stays on top of the PC graphics scene. News of the Radeon HD 6990’s arrival has been circulating for many months now, although back in the early days it was referred to by its codename—Antilles. Antilles was the codename given to the dual-Cayman GPU powered graphics card that would eventually top AMD’s graphics card line-up and supplant the Radeon HD 5970 that’s served the company so well, since its release way back in November of ’09.

While news of Antilles development wasn’t really news at all, considering AMD’s GPU design philosophy these past few years with the likes of the previous generation Radeon 4870 X2 and Radeon HD 5970, the actual final specifications of the Radeon HD 6990 were unclear for quite some time. Knowing the die size of a Cayman GPU and the power consumption characteristics of a single Radeon HD 6970 that employs one of these chips, some hypothesized (including yours truly) that pairing two of them on a single PCB, along with 4GB of RAM, would be no easy task. Some guessed that the card would have fewer stream processors enabled than a fully-equipped Cayman GPU or perhaps lower clocks than a Radeon HD 6970 and that its specs would place it somewhere in between Radeon HD 6950 and HD 6970 CrossFire configurations. However, it turns out AMD was actually able to cram what is essentially a pair of Radeon HD 6970s onto a single PCB. Sort of.

Take a gander at the specifications below and you’ll notice there’s two configurations of the Radeon HD 6990 listed. Those don’t represent two different cards, though. The Radeon HD 6990 actually sports two different BIOS configurations that can be used with a simple flip of switch. In one configuration, the Radeon HD 6990 falls within expected power limits, but in the other, the card will actually run beyond the PCIe power specs. It’s a pretty wild setup to say the least. You’ll see what we mean as we progress through the pages ahead and reveal all of the juicy details.

AMD Radeon HD 6990
Specifications & Features


The Radeon HD 6990 Arrived In This Hardened Case--Pretty Cool Stuff

A lot of engineering when into designing and building the Radeon HD 6990. So much so that it has spanned a few GPU generations. With that in mind, we’d suggest checking out a few past HotHardware articles to fully grasp everything that the Radeon HD 6990 has going on under its virtual hood. We won’t be rehashing many of the architectural details that have already been covered in previous articles:

In our coverage of the Radeon HD 6970 and 6950, we go in-depth regarding the architecture and features of AMD’s Cayman GPU, two of which power the Radeon HD 6990. In our reviews of the Radeon HD 5970 and 4870 X2, we talk of AMD’s GPU design philosophy and how the company has been able to use dual GPUs on a single PCB. And in the Catalyst Sneak Peek and X1950 coverage, we discuss some drive details and native CrossFire implementation.  But enough with history, let's look at AMD's new flagship.

AMD Radeon HD 6990 Exposed

Before we dive right in and inspect the Radeon HD 6990, let’s take a minute to look at its main features and specifications. Keep in mind as you look at the chart below that the card is built around a pair of GPUs, so some attributes are split between the two chips.

In its default, non-overclocked configuration, the Radeon HD 6990 has an 830MHz GPU frequency (@1.12v), with 1,250MHz memory (5.0Gbps effective data rate). There is 4GB of on-board frame buffer memory—2GB per GPU. There are a total of 3072 stream processors enabled, 192 texture units, and 64 ROPs. If you add all of this up, what it amounts to is roughly 2x of everything available on a reference Radeon HD 6970, save for the GPU clock (reference Radeon HD 6970 cards are clocked at 880MHz).

All of that horsepower requires a significant amount of juice to operate, so two supplemental 8-pin PCI Express power connectors are necessary with the Radeon HD 6990. And typical load board power can approach 375 watts, which is the maximum rating for a board with this power connector configuration (150 watts per 8-pin feed plus 75 watts from the PEG slot). Interestingly enough, as we mentioned on the previous page, with the flip of a switch, the Radeon HD 6990 can be run in an overclocked mode that pushes the GPU clock to 880MHz (@1.175). With the GPUs running at the higher clock and voltage, board power can exceed 415 watts, which also exceeds the power specifications, so using this mode is going to require a potent PSU. Powertune is configured to not exceed 375 watts when the 6990 is running in its stock configuration, but that number is upped to 450 watts when overclocked.



The Radeon HD 6990 is a full 12” long and the entire card is encased in a fan shroud on the front and a heavy duty metal heat-spreader on the back. A barrel-type cooling fan, common on all recent Radeons resides smack-dab in the middle of the card, which forces air across two heatsinks on either side, which are affixed to the pair of GPUs. Some of the heated air is expelled from the system through vents in the card’s mounting bracket, while the rest is exhausted out of the back of the card and into the system. In addition to making sure a system even has the room to fit a beast like this, good case cooling is also a must.



The output configuration on the Radeon HD 6990 consists of four mini-DisplayPort connectors and single dual-link DVI port. This card obviously supports AMD’s Eyefinity multi-display display technology and can drive up to five displays simultaneously. We should also note that the 6990, when used with an upcoming set of Catalyst drives will support 5x1 portrait Eyefinity configurations, which would make for some truly immersive gaming to say the least.
In a couple of the shots above, the BIOS switch which alternates between overclocked and stock configurations is visible, as are the output connectors, the card’s CrossFire bridge connector (yes, CrossFireX is supported) and board power connectors.

Physically, the Radeon HD 6990 is just a touch shorter than a Radeon HD 5970, due to the slight protrusions on the back of the 5970.

More 6990 Details, Catalyst Updates

A significant amount of engineering went into not only designing the Radeon HD 6990 PCB, but its cooling solution as well.



AMD made as much of the board and its component layout as symmetrical as possible. The regulators are located in the center of the board, with GPUs and their associated memory on either side. The board also uses a newer-generation of programmable Volterra regulators, which are more efficient than previous generations and offer higher current capacity relative to the previous solutions used by AMD. These new regulators also reportedly operate at lower temperatures and consume less power as well.


To keep everything on the card cooled, AMD employs a pair of vapor chambers with a centrally located blower. The vapor chambers are mounted to the GPUs, and are surrounded by an additional heat plate that cools the regulators and on-board RAM. AMD also uses a phase-change thermal interface material that’s reportedly offers up to 8% better performance than what AMD has used previously.



To coincide with the launch of the Radeon HD 6990, AMD is also announcing some new features and changes to the Catalyst software suite. In addition to adding support for 5x1 portrait Eyefinity configurations, starting with Catalyst 11.4, AMD will be incorporating a driver update notification system and a revamped Eyefinity user interface, with a task-based display management system. AMD will also be unveiling a new branding scheme to help better identify the graphics configuration in a system. In APU equipped systems, the drivers will be branded “AMD Vision Engine Control Center”, in workstations “AMD Catalyst Pro Control Center” and the “Catalyst Control Center” on desktop and gaming systems.

Test Setup & Unigine Heaven v2.1

How We Configured Our Test Systems: We tested the graphics cards in this article on a Gigabyte GA-EX58-UD5 motherboard powered by a Core i7 980X six-core processor and 6GB of OCZ DDR3-1333 RAM. The first thing we did when configuring the test system was enter the system BIOS and set all values to their "optimized" or "high performance" default settings. Then we manually configured the memory timings (DDR3-1333, CAS 7) and disabled any integrated peripherals that wouldn't be put to use. The hard drive was then formatted and Windows 7 Ultimate x64 was installed. When the installation was complete we fully updated the OS and installed the latest DirectX redist, along with the necessary drivers, games, and benchmark applications.

HotHardware's Test System
Intel Core i7 Powered

Hardware Used:
Core i7 980X (3.3GHz)
Gigabyte EX58-UD5 (X58 Express)

Radeon HD 6870
Radeon HD 6950 1GB
Radeon HD 6950
Radeon HD 6970
Radeon HD 6990
GeForce GTX 560 Ti
GeForce GTX 460
GeForce GTX 570
GeForce GTX 580

6GB OCZ DDR3-1333
Western Digital Raptor 150GB
Integrated Audio
Integrated Network

Relevant Software:
Windows 7 Ultimate x64
DirectX Nov. 2010 Redist
ATI Catalyst v11.1a/11.4b
NVIDIA GeForce Drivers 266.58

Benchmarks Used:

Unigine Heaven v2.1
Futuremark 3DMark11
FarCry 2
Just Cause 2
Alien vs. Predator
Metro 2033
Lost Planet 2
F1 2010*

* - Custom benchmark

Unigine Heaven v2.1 Benchmark
Pseudo-DirectX 11 Gaming

Unigine Heaven

The Unigine Heaven Benchmark v2.0 is built around the Unigine game engine. Unigine is a cross-platform real-time 3D engine, with support for DirectX 9, DirectX 10, DirectX 11 and OpenGL. The Heaven benchmark--when run in DX11 mode--also makes comprehensive use of tessellation technology and advanced SSAO (screen-space ambient occlusion), and it also features volumetric cumulonimbus clouds generated by a physically accurate algorithm and a dynamic sky with light scattering.

In a direct GPU vs. GPU comparison, the NVIDIA-built chips have a huge advantage in the heavily tessellated Unigine Heaven benchmark due to the strong geometry processing capabilities, but cram two AMD GPUs on a single card and graph skews heavily in the Radeon's favor. The new Radeon HD 6990 was the top performer by a wide margin here, besting the GTX 580 by approximately 50% and the Radeon HD 6970 by over 93%.

Futuremark 3DMark11

Futuremark 3DMark11
Synthetic DirectX Gaming

Futuremark 3DMark11

The latest version of Futuremark's synthetic 3D gaming benchmark, 3DMark11, is specifically bound to Windows Vista and 7-based systems because it uses the advanced visual technologies that are only available with DirectX 11, which isn't available on previous versions of Windows.  3DMark11 isn't simply a port of 3DMark Vantage to DirectX 11, though.  With this latest version of the benchmark, Futuremark has incorporated four new graphics tests, a physics tests, and a new combined test.  We tested the graphics cards here with 3DMark11's Extreme preset option, which uses a resolution of 1920x1080 with 4x anti-aliasing and 16x anisotropic filtering.

The high-end single-GPU powered cards, i.e. the Radeon HD 6970 and GeForce GTX 580, perform similarly in the 3DMark11 benchmark, with the GTX 580 holding on to a small lead. The dual-GPU powered cards like the Radeon HD 5970 and 6990, however, offer the top performance, with the ultra powerful Radeon HD 6990 finishing well ahead of the rest.

FarCry 2 Performance

FarCry 2
DirectX Gaming Performance

FarCry 2

Like the original, FarCry 2 is one of the more visually impressive games to be released on the PC to date. Courtesy of the Dunia game engine developed by Ubisoft, FarCry 2's game-play is enhanced by advanced environment physics, destructible terrain, high resolution textures, complex shaders, realistic dynamic lighting, and motion-captured animations.  We benchmarked the graphics cards in this article with a fully patched version of FarCry 2, using one of the built-in demo runs recorded in the "Ranch" map.  The test results shown here were run at various resolutions with 4X AA enabled.

The new AMD Radeon HD 6990 put up some impressive scores in the FarCry 2 benchmark. Here, AMD's new flagship graphics card blew past all of the competition by a wide margin.  The Radeon HD 6990 was between 43% and 65% faster than a GTX 580 and between 79% and 92% faster than the Radeon HD 6970.

Just Cause 2 Performance

Just Cause 2
DX10.1 Gaming Performance

Just Cause 2

Just Cause 2 was released in March 2010, from developers Avalanche Studios and Eidos Interactive. The game makes use of the Avalanche Engine 2.0, an updated version of the similarly named original. It is set on the fictional island of Panau in southeast Asia, and you play the role of Rico Rodriquez. We benchmarked the graphics cards in this article using one of the built-in demo runs called The Concrete Jungle.  The test results shown here were run at various resolutions and settings. This game also supports a few CUDA-enabled features, but they were left disabled to keep the playing field level. 

The Radeon HD 6990 performed exceptionally well in the Just Cause 2 benchmark. In this set of tests, the Radeon HD 6990 was about 67% faster than the GeForce GTX 580 at both resolutions and between 91% and 92% faster than the Radeon HD 6970.

Metro 2033 Performance

Metro 2033
DirecX11 Gaming Performance

Metro 2033

Metro 2033 is your basic post-apocalyptic first person shooter game with a few rather unconventional twists. Unlike most FPS titles, there is no health meter to measure your level of ailment, but rather you’re left to deal with life, or lack there-of more akin to the real world with blood spatter on your visor and your heart rate and respiration level as indicators. The game is loosely based on a novel by Russian Author Dmitry Glukhovsky. Metro 2003 boasts some of the best 3D visuals on the PC platform currently including a DX11 rendering mode that makes use of advanced depth of field effects and character model tessellation for increased realism. This title also supports NVIDIA PhysX technology for impressive in-game physics effects. We tested the game resolutions of 1920x1200 and 2560x1600 with 4X anti-aliasing and in-game image quality options set to thei High Quality mode, with DOF effects disabled.

The AMD Radeon HD 6990 rocked in the Metro 2033 benchmark as well. The Radeon HD 6990 was the only card to offer consistently playable framerates at the highest resolution here and it finished roughly 55% to 70% ahead of the best single-GPU powered cards currently on the market.

Lost Planet 2 Performance

Lost Planet 2
DirectX 11 Gaming Performance

Lost Planet 2

A follow-up to Capcom’s Lost Planet : Extreme Condition, Lost Planet 2 is a third person shooter that takes place again on E.D.N. III ten years after the story line of the first title. We ran the game’s DX11 mode which makes heavy use of DX11 Tessellation and Displacement mapping and soft shadows.  There are also areas of the game that make use of DX11 DirectCompute for things like wave simulation in areas with water.  This is one game engine that looks significantly different in DX11 mode when you compare certain environmental elements and character rendering in its DX9 mode versus DX11.  We used the Test B option built into the benchmark tool and with all graphics options set to their High Quality values.

Lost Planet 2 is another benchmark that heavily favors NVIDIA's GPU architecture. As such, the GeForces have no trouble manhandling the single-GPU powered Radeons here. With two GPUs at its heart, however, the new Radeon HD 6990 gets a huge performance boost and it takes the top spot once again, although it only beats the GeForce GTX 580 by about 6% to 20% depending on the resolution.

F1 2010 Performance

F1 2010
DirectX 11 Gaming Performance

F1 2010

Though Codemasters still continues to torture us with their ridiculously complicated labyrinth of game menus, we’ve found ourselves coming back to one of their titles for a taste of bleeding-edge DX11 benchmarking. F1 2010 is their latest racing simulation and like Dirt 2, it sports impressive visuals with DX11 support. “Ultra” settings for shadow effects and post processing elements like depth of field then become available to the gamer and in turn, crank up the workload on the graphics subsystem. The game engine also makes use of multi-core processors for higher performance on top-end systems. We tested the game configured with its Ultra graphics options at resolutions of 1920x1200 and 2560x1600.

The Radeon HD 6990 put up another dominant performance in the F1 2010 benchmark. Here, the dual-GPU powered Radeon HD 6990 was about 80% faster than both the Radeon HD 6970 and GeForce GTX 580 at the higher resolution. Its lead over the same top-end cards at lower resolutions are smaller, but still impressive with a 45% gain over the GeForce GTX 580 and a 55% gain over the Radeon HD 6970.

Alien vs. Predator Performance

Alien vs. Predator
DirectX 11 Gaming Performance

Alien vs. Predator

The Alien vs. Predator benchmark makes use of the advanced Tessellation, screen space ambient occlusion and high-quality shadow features, available with DirectX 11. In addition to enabling all of the aforementioned DirectX 11 related features offered by this benchmark, we also switched on 4X anti-aliasing along with 16X anisotropic filtering to more heavily tax the graphics cards being tested.

This graph is almost scary to look at. The Radeon HD 6990's performance here was roughly double that of the Radeon HD 6970 and about 86% faster than the GeForce GTX 580.

Total System Power Consumption

Before bringing this article to a close, we'd like to cover a few final data points--namely power consumption and noise. Throughout all of our benchmarking and testing, we monitored how much power our test system was consuming using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and while under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the graphics cards alone.

Total System Power Consumption
Tested at the Outlet

With what are basically two Radeon HD 6970 cards crammed onto a single PCB, we expected the Radeon HD 6990's power consumption to be relatively high in comparison to virtually all other high-end, current-gen graphics cards and that was in fact the case. Idle power consumption is fairly good; the Radeon HD 6990 actually consumes less than 20 watts more than the Radeon HD 6970 and less than 10 watts more than the GeForce GTX 580.  Under load conditions, however, the Radeon HD 6990's power consumption spikes way up and the card uses about 100 to 150 additional watts over a GeForce GTX 580, depending on the 6990's configuration.

At power consumption levels this high, it should come as no surprise that the Radeon HD 6990 can get somewhat noisy  under load. Temperatures, however, are kept in check thanks to some large heatsinks and a fan speed profile that gets air moving rather quickly, once temperatures ramp up.

Under load, the Radeon HD 6990 will definitely be audible over the noise a typical high-end PC generates from its cooling fans, drives, etc. We would not call the card excessively loud, however. Once the fan spins up above the 45% mark or so, its volume easily drowned out the other fans in our test bed, but the pitch of the fan wasn't annoying. It's probably in the same class as a pair of Radeon HD 5870 cards, perhaps just a bit louder.

As for temperatures, though, the AMD's fairly aggressive fan speed profile helps keep them manageable. We witnessed GPU temperatures in the mid-80'C range and watched the fan speed fluctuate from about 39% to 45%, which easily pulled the GPU temps back down closer to 80'C. While idle, the card didn't pump out very much heat at all and the fan is barely audible.

Our Summary and Conclusion

Performance Summary: Summarizing the Radeon HD 6990’s performance couldn’t be any easier. In every benchmark we ran and in every game we tested, regardless of the in-game settings or resolution used, the Radeon HD 6990 offered the best performance of any single-graphics card we’ve ever tested. The combination of two AMD Cayman-class GPUs and 4GB of fast GDDR5 memory on a single PCB result in extreme performance that’s significantly higher than the AMD Radeon HD 5970, Radeon HD 6970, or NVIDIA GeForce GTX 580. In short, unless (or until) NVIDIA releases its own dual-GPU powered card, it’s going to take two of the most powerful single-GPU based graphics cards available today to match or exceed the performance of the Radeon HD 6990.

AMD Radeon HD 6990

The AMD Radeon HD 6990 is an extreme graphics card in every sense of the word. The card’s performance is obviously extreme, as is its power consumption, its output configuration, and its price. AMD is setting the MSRP at whopping $699. This card is no doubt expensive, but considering its performance, along with a few other factors worth mentioning, we can see how AMD arrived at this number. At $699, the Radeon HD 6990 costs a little more than double that of the average Radeon HD 6970, which currently sells for about $340. With every Radeon HD 6990 though, two mini-DP to DVI adapters (one active, and one passive) will be included, along with a single mini-DP to HDMI adapter. Shipping with this assortment of adapters will allow Radeon HD 6990 owners to immediately set up a wide array if Eyefinity configurations, with virtually any type of monitor, without having to invest in additional adapters. So, in terms of its performance and accessories, we can see why AMD is setting the price where it has. We wish it was cheaper, and we suspect many of you are feeling the same way, but as usual, you gotta pay to play on the bleeding edge of the PC enthusiast space.

While we wish power consumption was a bit lower and the card was a little quieter under load, we can’t help but be impressed by the AMD Radeon HD 6990. This graphics card is simply a beast, there’s no other way to put it. But AMD’s efforts to tame this beast must also be commended. Having tested single-GPU powered cards over the years that were much louder and didn’t offer anywhere near the kind of dominant performance that the Radeon HD 6990 does, we can better appreciate what AMD has done here. The Radeon HD 6990 is not everyone, as is evident by its exorbitant price tag and power requirements, but for those uncompromising enthusiasts that want nothing but the best of the best, at any price, the Radeon HD 6990 delivers the goods.

Update: AMD sent word of a Radeon HD 6990 give-away they're running and asked that we get the word out.  Check out this site for a chance to win.

  • Extreme Performance
  • Playable 5-way Eyefinity From a Single Card
  • 4GB On-Board
  • Overclocked At The Flip of a Switch

  • High Power Consumption
  • Pricey
  • A Little Loud Under Load

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