Yes, with regards to performance, Nvidia GeForce GTX 1080 Ti outperforms, Radeon RX Vega 56 by 37.7% 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. RX Vega 56's efficiency score is 32 .So GTX 1080 Ti leads by 15.6%, making it the smarter choice in terms of power consumption.
When considering value for money, GTX 1080 Ti offers a better deal than, Radeon RX Vega 56 by 20.0%.