The backward compatible version of Halo: Reach on Xbox One currently suffers from sometimes severe frame rate issues, with some players reporting that the rate drops into the teens at times. Microsoft says they're aware of the problems and working to improve the game's frame rate.
The Xbox 360 version of the game maintains a steady 30FPS setting and Microsoft has told Kotaku, “We’re aware some users are experiencing issues playing Halo: Reach via Xbox One Backward Compatibility. The Xbox engineering team is currently looking into the issues and are working to address them."
Halo: Reach is the only entry in the Halo series from the Xbox or Xbox 360 era not included in the Master Chief Collection. While not originally available, Halo 3: ODST was later released for the Collection.
Reach was one of 16 games launched as part of the Xbox One's backward compatibility service earlier this month.