Clearly just a guess, but based off what they did with Maxwell...
- Summer 2016 - Mid Tier - GP104 (970/980 updates; 6GB of GDDR5X; 980 Ti performance; $400-500)
- Fall/Winter 2016 - Low Tier - GP106 (950/960 updates; 4GB of GDDR5; 970/980 performance; $200-300)
- Spring 2017 - Uber Tier - GP100 (Titan X update; 16GB of HBM2; 50% performance increase over Titan X; $1000)
- Summer 2017 - High Tier - GP100 (980 Ti update; 8GB of HBM2; 50% increase over 980 Ti; $650-700)
Moves all current performance/memory down one tier on the hierarchy, representing an upgrade across the board. Quarterly updates keeps the product line fresh. Releasing the Mid Tier and God/High Tier nearly a year apart allows Nvidia to double dip on the enthusiasts who want the latest and greatest.
you forgot GP102