For testing the power consumption of our test system with the ASUS GTX 560 DirectCU II Top we connected a Kill-A-Watt EZ to the power connection. For idle numbers we allowed the system to idle for 15 minutes on the desktop screen and took a reading.
To show peak overall system power draw we ran two different tests. The first was several loops of Alien vs. Predator benchmark with all settings maxed out. This represents real world gaming and a typical load that would be placed on the system and graphics card.
The second test , FurMark 1.9.1, has considerable controversy due to the synthetic nature of the test and the extreme load it places on video cards. It is well known that both NVIDIA and AMD (ATI) have blacklisted both FurMark and OCCT so that when the drivers detect one of these programs they tell the power limiters on the card to under clock the cards to keep them from pulling more than the 300W specification on the PCI-E power lines.
Quote from NVIDIA Tech Support:
Furmark is an application designed to stress the GPU by maximizing power draw well beyond any real world application or game. In some cases, this could lead to slowdown of the graphics card due to hitting over-temperature or over-current protection mechanisms. These protection mechanisms are designed to ensure the safe operation of the graphics card. Using Furmark or other applications to disable these protection mechanisms can result in permanent damage to the graphics card and void the manufacturer’s warranty.
However this is dependent on the manufacturer as some employ this reference design feature and others do not with ASUS currently being one who does not do this. Also there is some discussion as if FurMark 1.9.x has made it on the blacklist yet for NVIDIA drivers to detect.
In order to show that absolute worst case scenario we added in the power draw during the FurMark stress test for informational purposes. This is by no means real world so do not expect to have this level of power draw during normal gaming sessions. This number show that ASUS is not limiting power based on the use of FurMark 1.9.1 currently.
Total System Power Consumption:
The down side of overclocking, your power usage goes up a bit but the additional 15 Watts should not hit your wallet too hard.
**Note: Kill-A-Watt has a 0.2% margin of error.