AMD introduced its first Radeon HD 6000 graphics card last October, when we reviewed the mid-range Radeon HD 6870. Since then AMD opened up to show its GPU roadmap and the cards that soon thereafter were coming to market.
The high-end Radeon HD 6970 and HD 6950 also arrived late last year, while the dual-GPU version of AMD's last generation graphics series code-named Antilles was expected to arrive shortly after. Coincidentally (or not) both AMD and Nvidia took a few months longer than expected to show its hardcore dual-GPU graphics cards, with the former making the first move to finally unveil the Radeon HD 6990.
Having looked at most of the previous generation Crossfire and SLI products, we were certainly looking forward to see what AMD had in store for us with this dual-GPU monster.
We don't think AMD sells large volumes of these dual-GPU cards, in fact, previous versions of their topmost offerings have been known to disappear from retail temporarily and then stock back up again. Having that said, the Radeon HD 6990 is an important product on AMD's line-up as it can do a lot for the series reputation, just as the HD 5970 did before.
With both AMD and Nvidia trying hard to push its graphics technologies beyond PC gaming, including the use of embedded graphics in motherboards and processors, that has also meant that the discrete GPU market on the low-end segment is shrinking and thus mid-range offerings are taking a new level of precedence.
Holding the performance crown can be a big deal, and AMD did so uncontested for quite some time with the Radeon HD 5970. As you may recall, the GeForce GTX 400 series was simply too hot to stick a pair of GPUs on a single PCB and therefore Nvidia was never able to respond with a dual-GPU offering of their own. Nvidia has overcome all those issues now, having also released their latest generation architecture with multiple GeForce 500 series products on offer today.
The GeForce GTX 580 is able to match the dual-GPU Radeon HD 5970 and even beat it in a number of areas. With the arrival of the Radeon HD 6990, AMD is hoping to take back the performance crown which they will likely hold until the GeForce GTX 590 arrives.
Under the hood, the Radeon HD 6990 is essentially a pair of underclocked Radeon HD 6970 GPUs on top of a massive PCB. This is the same of what we found with the Radeon HD 5970 which featured a pair of HD 5870 GPUs operating at slightly lower frequencies.
When designing the older Radeon HD 5970, AMD worked hard to keep within the PCI Express specification which calls for a maximum TDP of 300 watts. At 294 watts the HD 5970 just scrapped in and was still the most power hungry graphics card of its time. However, the new Radeon HD 6990 is much closer in specification to the HD 6970 than the HD 5970 was to the HD 5870. As a result the card's TPD rating has increased to a staggering 375 watts.
Perhaps for some that won't be the biggest shocker. The new Radeon 6990 is set to sell for $699, which translates in a $100 premium versus the HD 5970's price at launch. At this price point gamers can alternatively purchase a pair of Radeon HD 6970 cards and still save a few bucks while scoring a little extra performance. With that in mind, let’s check out the almighty Radeon HD 6990 in better detail.
Radeon HD 6990 In Detail
The Radeon HD 6990 is a massive graphics card measuring in at 12 inches long (30cm) and weighing a little over 1kg. This puts it on par with the Radeon HD 5970, AMD’s previous flagship dual-GPU graphics card. Our review sample hung 6cm off the edge of our Asus P6T Deluxe motherboard used for testing.
Cooling the Antilles GPUs is a pair of large aluminum heatsinks made up of 37 fins each. The heatsinks are separated by a blower fan which is positioned in-between them rather than at the end of the card. This design is said to be more efficient as it will allow the fan to spin at a lower RPM yet provide the same amount of air across both heatsinks.
The real key to this design is the use of vapor chambers and high endurance thermal compound. AMD has also provided adequate cooling for the card's GDDR5 memory chips and VRMs using aluminum heatsink plates which span the length of the card, back and front.
The vapor chamber design was first implemented in the Radeon HD 5970 and has already been used on other HD 6000 series graphics cards, however the HD 6990 features two of them. We are going to have to rely on photos from AMD to show you this. AMD claims the GPUs on the HD 6990 use a special kind of “phase change” thermal compound which improves thermal performance by 8% when compared to previous cards. Removing the heatsinks would basically bust this, or so we are told.
For the most part the card's fan operates quietly, helped by its impressively low 37-watt idle consumption. When gaming, the fan will inevitably spin up as the Radeon HD 6990 can consume a sweltering 375 watts under load, and then when pushed hard the card does begin to sound like a leaf blower.
The heatsink and fan have been enclosed within a custom-built housing that conceals the entire graphics card, same as we saw on its predecessor. This setup helps protect the card very well; Nvidia has been using similar enclosures for some time as well on certain products.
Removing the heatsink exposes the two GPUs, GDDR5 memory chips, and a few other critical components.
With the heatsink off the Radeon HD 6990 looks considerably different than the HD 5970. The biggest change is the position of the GPUs, whereas the Radeon HD 5970 had them next to each other, they are now at opposite ends of the 12” long graphics card.
The GDDR5 memory works at 5000MHz (1.25GHz x 4) on this particular model and features a 4GB capacity. This gives each GPU a theoretical memory bandwidth of 160GB/s thanks to the implementation of a 256-bit wide memory bus.
Although the Radeon HD 6990 is not clocked as aggressively as the single-GPU HD 6970, with a core clock frequency of 830MHz it is still faster than the HD 6950. Simple math will tell you that because the Radeon HD 6990 is clocked roughly 6% lower than the HD 6970, it will be slightly slower than a pair of these graphics cards operating in Crossfire mode.
The core configuration of the Radeon HD 6990 calls for 1536 SPUs, 96 TAUs (Texture Address Units), and 32 ROPs (Rasterization Operator Units) per GPU giving a total of 3072 SPUs, 192 TAUs, and 64 ROPs.
A pair of 8-pin PCI Express power connectors are used to feed the graphics card enough power. This is the first time we've come across a reference board that requires a pair of 8-pin connectors. That said, the Crossfire equivalent would not only require two 8-pin power cables but also a pair of 6-pin connectors as well.
The Radeon HD 6990 naturally supports CrossfireX, and therefore in the standard position we find a single connector for bridging two cards together.
The only other connectors can be found on the I/O panel. Our review board featured a single dual-DVI connector along with an array of four Mini Display Port connections. With Eyefinity the HD 6990 can support a max resolution of 2560x1600 on six monitors, while standard cards can support up to five.
Cooling the Antilles GPUs is a pair of large aluminum heatsinks made up of 37 fins each. The heatsinks are separated by a blower fan which is positioned in-between them rather than at the end of the card. This design is said to be more efficient as it will allow the fan to spin at a lower RPM yet provide the same amount of air across both heatsinks.
The real key to this design is the use of vapor chambers and high endurance thermal compound. AMD has also provided adequate cooling for the card's GDDR5 memory chips and VRMs using aluminum heatsink plates which span the length of the card, back and front.
The vapor chamber design was first implemented in the Radeon HD 5970 and has already been used on other HD 6000 series graphics cards, however the HD 6990 features two of them. We are going to have to rely on photos from AMD to show you this. AMD claims the GPUs on the HD 6990 use a special kind of “phase change” thermal compound which improves thermal performance by 8% when compared to previous cards. Removing the heatsinks would basically bust this, or so we are told.
For the most part the card's fan operates quietly, helped by its impressively low 37-watt idle consumption. When gaming, the fan will inevitably spin up as the Radeon HD 6990 can consume a sweltering 375 watts under load, and then when pushed hard the card does begin to sound like a leaf blower.
The heatsink and fan have been enclosed within a custom-built housing that conceals the entire graphics card, same as we saw on its predecessor. This setup helps protect the card very well; Nvidia has been using similar enclosures for some time as well on certain products.
Removing the heatsink exposes the two GPUs, GDDR5 memory chips, and a few other critical components.
With the heatsink off the Radeon HD 6990 looks considerably different than the HD 5970. The biggest change is the position of the GPUs, whereas the Radeon HD 5970 had them next to each other, they are now at opposite ends of the 12” long graphics card.
The GDDR5 memory works at 5000MHz (1.25GHz x 4) on this particular model and features a 4GB capacity. This gives each GPU a theoretical memory bandwidth of 160GB/s thanks to the implementation of a 256-bit wide memory bus.
Although the Radeon HD 6990 is not clocked as aggressively as the single-GPU HD 6970, with a core clock frequency of 830MHz it is still faster than the HD 6950. Simple math will tell you that because the Radeon HD 6990 is clocked roughly 6% lower than the HD 6970, it will be slightly slower than a pair of these graphics cards operating in Crossfire mode.
The core configuration of the Radeon HD 6990 calls for 1536 SPUs, 96 TAUs (Texture Address Units), and 32 ROPs (Rasterization Operator Units) per GPU giving a total of 3072 SPUs, 192 TAUs, and 64 ROPs.
A pair of 8-pin PCI Express power connectors are used to feed the graphics card enough power. This is the first time we've come across a reference board that requires a pair of 8-pin connectors. That said, the Crossfire equivalent would not only require two 8-pin power cables but also a pair of 6-pin connectors as well.
The Radeon HD 6990 naturally supports CrossfireX, and therefore in the standard position we find a single connector for bridging two cards together.
The only other connectors can be found on the I/O panel. Our review board featured a single dual-DVI connector along with an array of four Mini Display Port connections. With Eyefinity the HD 6990 can support a max resolution of 2560x1600 on six monitors, while standard cards can support up to five.
Test System Specs & 3Dmark 11
Test System Specs
- Intel Core i7 920 (Overclocked @ 3.70GHz)
- x3 2GB G.Skill DDR3 PC3-12800 (CAS 9-9-9-24)
- Asus P6T Deluxe (Intel X58)
- OCZ ZX Series (1250w)
- Seagate 500GB 7200-RPM (Serial ATA300)
- Gigabyte Radeon HD 6990 (4GB)
- Gigabyte Radeon HD 6970 (2GB) Crossfire
- Gigabyte Radeon HD 6970 (2GB)
- Asus Radeon HD 6870 (1GB)
- HIS Radeon HD 5970 (2GB)
- HIS Radeon HD 5870 (1GB)
- HIS Radeon HD 5850 (1GB)
- Asus GeForce GTX 580 (1.5GB)
- Gigabyte GeForce GTX 570 (1.3GB)
- Gigabyte GeForce GTX 560 Ti (1GB)
- Inno3D GeForce GTX 480 (1.5GB)
- Palit GeForce GTX 470 (1.3GB)
- Gigabyte GeForce GTX 460 (1GB)
Software
- Microsoft Windows 7 Ultimate 64-bit
- Nvidia Forceware 267.24
- AMD Catalyst 11.2
- AMD Catalyst 11.4 Preview
Using 3Dmark 11 we measured the performance of the new Radeon HD 6990 using the Performance and Extreme profiles. The Extreme test saw the Radeon HD 6990 score 3353pts which is the highest figure generated by any single graphics card to date. This made it 34% faster than the Radeon HD 5970 and 71% faster than the GeForce GTX 580. However, when put against the Radeon HD 6970 Crossfire configuration the Radeon HD 6990 was 4% slower.
- Intel Core i7 920 (Overclocked @ 3.70GHz)
- x3 2GB G.Skill DDR3 PC3-12800 (CAS 9-9-9-24)
- Asus P6T Deluxe (Intel X58)
- OCZ ZX Series (1250w)
- Seagate 500GB 7200-RPM (Serial ATA300)
- Gigabyte Radeon HD 6990 (4GB)
- Gigabyte Radeon HD 6970 (2GB) Crossfire
- Gigabyte Radeon HD 6970 (2GB)
- Asus Radeon HD 6870 (1GB)
- HIS Radeon HD 5970 (2GB)
- HIS Radeon HD 5870 (1GB)
- HIS Radeon HD 5850 (1GB)
- Asus GeForce GTX 580 (1.5GB)
- Gigabyte GeForce GTX 570 (1.3GB)
- Gigabyte GeForce GTX 560 Ti (1GB)
- Inno3D GeForce GTX 480 (1.5GB)
- Palit GeForce GTX 470 (1.3GB)
- Gigabyte GeForce GTX 460 (1GB)
Software
- Microsoft Windows 7 Ultimate 64-bit
- Nvidia Forceware 267.24
- AMD Catalyst 11.2
- AMD Catalyst 11.4 Preview
Using 3Dmark 11 we measured the performance of the new Radeon HD 6990 using the Performance and Extreme profiles. The Extreme test saw the Radeon HD 6990 score 3353pts which is the highest figure generated by any single graphics card to date. This made it 34% faster than the Radeon HD 5970 and 71% faster than the GeForce GTX 580. However, when put against the Radeon HD 6970 Crossfire configuration the Radeon HD 6990 was 4% slower.
Power Consumption & Temperatures
Power consumption levels of the Radeon HD 6990 are considerably better than a pair of HD 6970 Crossfire cards, using 15% less power under stress conditions. When compared to a single GeForce GTX 580 graphics card, the Radeon HD 6990 used 18% more power to deliver on average 48% better performance.
Thermals were also kept in check, however the Radeon HD 6990 is easily the loudest graphics card we tested. You could say AMD's efforts to keep the card running cool were successful, but they completely forgot the "quiet" part of the equation. Still with a maximum temperature of 88 degrees we were surprised, even with the noise.
Source :
http://www.techspot.com/review/373-amd-radeon-6990/
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