Results: 3D Mark Firestrike
The latest version of 3D Mark can really push cards to their limit. I used the standard setting rather than extreme in this test.
In the more complex workload of Firestrike we see the 280X step away from the GTX 770, but it still cannot compete with the GTX 780. Overall performance of the GTX 780 nearly matches that of the CrossFired 270X.