In the power usage test we once again witness the excellent work that AMD has done in terms of idle usage. A second card is almost completely powered down when idling on the Windows desktop, using less than 3 watts. The difference we measured in SLI is quite significant. Idle our system used 96.4 watts with two HD 7970s, with two GTX 680s it used 114,5 watts.
The tables are turned in Metro 2033, however. With two HD 7970s we measured 511 watts, but with two GTX 680s the usage did not go above 475.7 watts.
Measurements for triple-SLI will soon we added. Since we had to test quad-SLI on a different motherboard, those results are not comparable.