Thing of their poor margins!
When GV100 was first announced, I though the only way they're going to increase performance for Volta (the same applies to Ampere) is by increasing the die size.
There are basically three ways to increase performance of GPUs:
- Clock it faster
- Enhance the architecture to get more done per clock tic.
- Add more shaders
Well, for 1. they probably won't get that much more out of it since TSMC don't seem to boast of clock enhancements with their '12nm' node.
For 2., I'm sure they'll try some ideas but the big efficiency gain they managed from Kepler to Maxwell is not likely to be repeated anytime soon.
So that only leaves them with 3. adding more shaders. Unless they can make those smaller, that means larger dies.
GP104 and even GP102 have plenty of space to grow, but their margins will suffer. I'd imagine they've targetted a certain extra performance for any new cards but I suspect it will in the low range of what people would be expecting. Still, +20% to +30% should allow the 1080 replacement to reach 1080Ti speeds.