Yes, with regards to performance, Nvidia GeForce GTX 1080 Ti outperforms, GeForce GTX 980 Ti by 61.1% in 3Dmark benchmark.
The GTX 1080 Ti is more energy-efficient considering its performance, having power consumption of 250 watts and a 3DMark score of 9333. By comparing its benchmark score to its power consumption, we get an efficiency score of 37. GTX 980 Ti's efficiency score is 23 .So GTX 1080 Ti leads by 60.9%, making it the smarter choice in terms of power consumption.
When considering value for money, GTX 1080 Ti offers a better deal than, GeForce GTX 980 Ti by 71.4%.