Radeon HD 6990

With the release of the Cayman GPU, the new GPUs don't perform as well against the competition as they did when Cypress was announced. Radeon HD 6970 accelerators are able to compete only with the GeForce GTX 570, but not with the flagship of the "green" - GeForce GTX 580. As part of the chosen strategy for AMD, it is quite a logical step to release a dual-processor solution based on the Cayman GPU, and today we are in once again offer to witness the change of power. This time the AMD Radeon HD 6990 graphics accelerator, also known under the code name Antilles, claims to be the champion.

I would like to say right away that no revolutionary changes in the architecture of the Radeon HD 6990 GPU have occurred. As in the case of the Radeon HD 5970, the new product is nothing more than a slightly slow Cayman CrossFireX tandem on a single board. However, this doesn't make the dual-chip monster less interesting, since AMD engineers used a number of unusual solutions when developing the HD 6990.

The dual BIOS appeared in serial samples of AMD accelerators, starting with the Radeon HD 6950/6970, then the reference samples of AMD accelerators were equipped with a duplicate microcircuit, write-protected and containing settings that were safe from the manufacturer's point of view. Now the second BIOS chip contains a slightly modified firmware, in which, in addition to the increased voltage on the GPU (from 1.12 to 1.175 V), the clock frequency of both graphics chips has been increased from 830 to 880 MHz (exactly like the Radeon HD 6970) . True, by providing such an opportunity, AMD refuses warranty obligations in case of damage to the video card when using alternative firmware. Another good news for all enthusiasts is the expansion of the clock speed limit, which can be set using the AMD OverDrive utility built into the Catalyst drivers.

The maximum power consumption of the Radeon HD 6990 with the active PowerTune technology is 450 watts. I must say, the Radeon HD 6990 is a very voracious little thing, so for the stable operation of the accelerator, AMD engineers modified the PCB wiring and improved the power system compared to analogues of previous generations. Symmetrical wiring allows you to provide stable power not only to both GPUs, but also to the sets of memory chips that serve them. In addition, colder elements were used in the power system.

As a cooling system, a significantly redesigned turbine is used, which, in comparison with previous counterparts from AMD, should provide 20% more powerful airflow. The thermal interface between the cooling system and the graphics chips is performed by a special compound called Phase change material, thanks to which, according to AMD, the heat transfer efficiency has been improved by 8%.

It is already obvious that the performance of the AMD Radeon HD 6990 is at a fairly high level, which is why AMD is literally pushing the owners of new cards to build Eyefinity configurations. To do this, each Radeon HD 6990 accelerator will be supplied with three adapters: passive miniDP->SL-DVI, active miniDP->SL-DVI and passive miniDP->HDMI.

The leitmotif of the presentation dedicated to the Radeon HD 6990 was the idea of ​​achieving maximum quality in existing games. To do this, AMD suggests using multi-monitor configurations, coupled with image quality improvement techniques such as Morphological Anti-Aliasing (MLAA) and Enhanced Quality Anti-Aliasing - EQAA. The manufacturer claims 69 games certified for Eyefinity and hundreds more projects that are compatible with this technology. By the way, the new Eyefinity 5x1 portrait mode will be supported by such expected novelties as Dragon Age II, Total War: Shogun 2, DiRT 3 and Deus Ex: Human Revolution.

The design of the cooling system is not much different from what we saw in the Radeon HD 6970, except that the accelerator itself has become larger and the turbine has moved from the “tail” to the center of the video card. By the way, the dimensions of the Radeon HD 6990 are comparable to those of the Radeon HD 5970, so if your case could fit the latter, then the Radeon HD 6990 will fit without difficulty.

There are 4 miniDP connectors and one DL-DVI connector on the output panel. Connecting devices that are incompatible with these interfaces, AMD suggests using appropriate adapters. Since the company promised to put three adapters in each box with the Radeon HD 6990, the owners of these video cards will have no problems with connecting output devices. Thanks to the placement of all connectors in one row, the upper part of the plug was completely given over to the ventilation grill, through which hot air is ejected by the turbine outside the system unit.

Not far from the CrossFireX connector is the BIOS chip switch. By default, it is set to "2", which means that the video card will work with the frequency formula 830/5000 MHz for the graphics core and video memory, respectively. But as soon as you switch it to position 1, the video card starts working at 880/5000 MHz. Of course, it is necessary to change the position of the toggle switch when the system is powered off.

To power the Radeon HD 6990, you need to connect two eight-pin PCI-Ex connectors. At the moment, this video card is one of the fastest graphics solutions on the market, showing performance approximately equal to the GeForce GTX 590.