If you guys look at GPGPU Benchmarks
http://www.anandtech.com/bench/GPU16/1512

You will notice that the 480 8GB will at max be 20% faster than the 290 under full optimization.

Comparing the results


480 8GB - 120MH/s
290 - 107MH/s
280x - 83.3MH/s
7850 - 45.5MH/s

Using the same ratios that leads to Claymore software

Nano - 98 Sol/s <- should be around here Optimally
Fury X - 96Sol/s <- should be around here Optimally
480 8GB - 96Sol/s <- should be around here Optimally.
290 - 75 Sol/s
280x - 55Sol/s
7850 - 30Sol/s

We are FVCKED if some developer released a Optimized Nvidia ZEC miner however because if its released and uses a similar hashing algo as Claymore then...

GTX 1080 - 262MH/s
GTX 1070 - 224.4MH/s
980Ti - 213.6MH/s

Converting to what we have now


GTX 1080 - 183Sol/s
GTX 1070 - 157Sol/s
980Ti - 150Sol/s


Thank god all the Nvidia miner devs are greedy and keeping everything PRIVATE.