Corsair Blog

Today’s high end video cards demand more power than ever and with multiple card configurations,  like the 4-Way SLI configuration detailed here, power demand is increased even more. In order to test how much power was being drawn from the wall, four NVIDIA® GeForce® GTX 480 video cards were installed onto a Gigabyte™ GA-X58A-UD9 motherboard. The entire setup would be powered by a single Corsair Professional Series™ Gold AX1200 power supply. To measure power draw a Kill A Watt™ meter was used with an accuracy rating of 2%.

System Specs:

• Motherboard: Gigabyte GA-X58A-UD9
• CPU: Intel® Core™ i7 920 @ 3.8GHz
• CPU Cooler: Corsair Air Series™ A50 CPU cooler in push-pull configuration
• Graphics Cards: NVIDIA® GeForce® GTX 480 x 4
• Power Supply: Corsair Professional Series™ Gold AX1200
• Memory: Corsair Dominator® GT DDR3 — CMG6GX3M3A2000C7
• SSD: Corsair Force Series™ F120

In order to power all of the video cards, a 4 pin molex to 6-Pin PCI-E power adapter was used on the last card. Another important thing to remember when running multi card configurations is to plug in any secondary PCI-E power on the motherboard. The Gigabyte UD9 motherboard that I used had a standard 4 pin molex connector above the top PCI-E x16 slot as well as along the bottom edge of the board. This will help the PCI-E slots get enough power for the cards.

A combination of games, benchmarks, and testing software were used to see how much power was being pulled from the wall. This software included 3DMark Vantage, Unigine™ Heaven benchmark, Mafia II and EVGA® OC Scanner. 3DMark Vantage simulates game play, and is known to put a heavy load onto the graphics card similar to the most demanding games. The Unigine Heaven benchmark is a newer benchmark, and features new technology like DirectX 11. Mafia II was chosen since it is a fairly new and popular game. Finally, the EVGA OC Scanner was chosen as we happened to know it would pull the most power out of any of the other software.

With 4-Way SLI properly configured the first wattage reading taken was at idle. The reading was taken after starting the system and letting it sit for five minutes. The reading was 457 watts.

The first benchmark 3DMark Vantage did a very good job of simulating the most demanding games. During the graphics tests the lowest wattage reading recorded was 794 watts, while the highest reached 1145 watts. The average power draw through the graphics tests in this benchmark was 1072 watts.

Unigine Heaven was up next, which uses the latest DirectX 11 technology. The benchmark was left on default settings and run at 1680 x 1050 resolution. The maximum wattage pull seen during this benchmark was 1013 watts, while the lowest seen was 842 watts. The average power draw ended up at 968 watts.

While benchmarks are great for testing, using one of the newest games is also a great way to test. New games always include features to take advantage of the latest and greatest video cards. In Mafia II game play and benchmark the highest wattage seen was 885 watts and the lowest was 640 watts. The average power draw was 794 watts after 20 minutes of game play.

The final test run was using EVGA’s OC Scanner. Now, while this utility is normally used for trouble shooting, it has the ability to strain the graphics cards to a higher degree than any known game or application. Getting the most power draw from this utility requires setting the resolution to the maximum supported by your monitor, and checking the box to unlock power draw. (NOTE: It is not recommended to check the unlock power draw box as it may damage your video card.)

The maximum power draw seen with this test was an impressive 1489 (!) watts, while the lowest was 1356 watts. The power supply was pulling over 1400 watts for ten minutes while this test was run! At the AX1200’s rated efficiency of about 88% at full load, this means that the system was using an average of 1232 watts over this ten minute period, and peaked at over 1300 watts.

Don't try this at home, kids!

Overall the Professional Series Gold AX1200 PSU stood up to all of the testing and abuse without a single hiccup including the OC Scanner torture test. Although the OC Scanner is far above what a game or benchmark will do, the AX1200 handled it with ease. Repeating the test yielded the same power consumption results, and the same solid system stability. Impressive!