Since there is no Founders Edition model for the GeForce GTX 1660, cooling performance will vary between the custom solutions implemented by different vendors. The Phoenix card with me today employs just a single fan for cooling, which is probably why it ran hotter than the dual-fan ROG Strix model, despite being the less powerful card.
In fact, compared to the rest of the cards, cooling performance is quite disappointing, as even the GeForce RTX 2060 Founders Edition ran cooler.
When it came to power consumption, the card performed quite similarly to the GeForce GTX 1060, albeit with higher idle power draw. The numbers here also highlight just how inefficient AMD's Radeon RX 590 is, as NVIDIA consistently beats it in terms of performance per watt.