Yes, with regards to performance, Nvidia GeForce GTX 1660 outperforms, GeForce GTX 1060 by 29.4%.
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. GTX 1060's efficiency score is 35.1, 29.4% lower, making GTX 1660 the smarter choice in terms of power consumption.
When considering value for money, GTX 1660 offers a better deal than, GeForce GTX 1060 by 127.3%. Here is more in depth overview of the price and used prices of GTX 1660 Price History and GTX 1060 Price History