DirectX 11 is the only way to go.
The PC requirements for Quantum Break on Steam have been revealed and unfortunately, DirectX 12 support doesn’t appear to be included. Instead, Remedy Entertainment opted for DirectX 11 which seems to indicate that DirectX 11 support won’t be coming to the Windows 10 version.
A developer for Remedy also noted on the Steam forums that SLI would not be supported either. “Like mentioned on other topics, the game doesn’t support SLI. But even with one GTX 1080 and the right settings, you should be able to get an enjoyable experience out of the game. I recommend comparing visual differences between ‘high’ and ‘ultra’ options in different areas of the display settings page.”
Quantum Break arrives on September 29th for Steam after launching for Xbox One and Windows 10 PCs earlier this year. The Windows 10 version is rather infamous for its launch problems and optimization issues so hopefully the same fate doesn’t befall the Steam version. Check out the Steam requirements here.