No, in terms of performance, Nvidia GeForce GTX 1660 is slower than, AMD Radeon RX Vega 56 by -24.2%.
The GTX 1660 is more energy-efficient considering its peformance, consuming 120 watts to produce 3DMark score of 5454. By comparing its benchmark score to its power consumption, we get an efficiency score of 45.5. RX Vega 56's efficiency score is 32.3, 40.9% lower, making GTX 1660 the smarter choice in terms of power consumption.
When considering value for money, GTX 1660 offers a better deal than, Radeon RX Vega 56 by 150.0%. Here is more in depth overview of the price and used prices of GTX 1660 Price History and RX Vega 56 Price History