Update 8/26: The source that claimed Quantum Break won two awards at SIGGRAPH 2015 is in question. I apologize for the confusion.
A presentation hosted by Remedy Entertainment included a document that reveals Quantum Break will run at 1080p. As you can see in the image below, shadows and lighting within the game are evaluated at a resolution of 720p but the actual image will be in 1080p. This may have been the source of some confusion for other media outlets who erroneously reported that the game will run in 720p on Xbox One. Remedy has also confirmed that Quantum Break will have a frame rate on par with other third person shooters at 30fps.
A tip of the hat to our friends at ICXM for spotting this story.