|AMD Radeon HD 6990 Antilles Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Olin Coles|
|Tuesday, 08 March 2011|
Page 17 of 18
VGA Power Consumption
For power consumption tests, Benchmark Reviews utilizes an 80-PLUS GOLD certified OCZ Z-Series Gold 850W PSU, model OCZZ850. This power supply unit has been tested to provide over 90% typical efficiency by Chroma System Solutions. To measure isolated video card power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International.
A baseline measurement is taken without any video card installed on our test computer system, which is allowed to boot into Windows 7 and rest idle at the login screen before power consumption is recorded. Once the baseline reading has been taken, the graphics card is installed and the system is again booted into Windows and left idle at the login screen before taking the idle reading. Our final loaded power consumption reading is taken with the video card running a stress test using FurMark. Below is a chart with the isolated video card power consumption (system without video card minus measured total) displayed in Watts for each specified test product:
* Results are accurate to within +/- 5W.
In the previous section we discovered how well the new and improved AMD cooling solution managed temperatures for a pair of Cayman GPUs on the Radeon HD 6990 video card. In terms of power consumption, the results were generally similar. Keeping in mind that the Radeon HD 6990 houses two independent high-performance graphics processors, it's expected that the graphics card will require significant power even despite the use of new Volterra regulators. The Radeon HD 6990 accepts two 8-pin PCI-E power connections for proper operation, and will not display a picture on the screen unless proper power has been supplied.
The power consumption statistics discussed below are absolute maximum values, and not representative of real-world temperatures while gaming:
Resting at idle with no GPU load, the Radeon HD 6990 consumed a 46W - or roughly 23W per GPU by our measure. This level of power consumption was identical between standard and OC positions on the dual-BIOS. Compensating for a small margin of error, this also roughly matches idle power draw from the ATI Radeon HD 5970 video card. Once 3D-applications begin to demand power from the Cayman GPUs, electrical power consumption climbs. Measured at full throttle with FurMark's multi-GPU 3D torture load, the Radeon HD 6990 topped out at 350W maximum power draw and matches AMD's stated max TDP. Under full load using the OC setting on the dual-BIOS, measured maximum power draw climbed to 368W. Our measurements are absolute maximums, since Furmark is not representative of real-world gaming power draw.