GeForce GTX 1080 Ti vs GeForce GTX 1660 Ti specs and performance
For gaming, the GeForce GTX 1080 Ti graphics card is better than the GeForce GTX 1660 Ti in our tests.
The GeForce GTX 1660 Ti has a slightly higher core clock speed. This is the frequency at which the graphics core is running at. While not necessarily an indicator of overall performance, this metric can be useful when comparing two GPUs based on the same architecture. In addition, the GeForce GTX 1660 Ti also has a slightly higher boost clock speed. The boost clock speed is the frequency that the GPU core can reach if the temperature is low enough. The allows for higher performance in certain scenarios.
Furthermore, the spec sheet for both these GPUs show that the GeForce GTX 1080 Ti has significantly more memory with 11 GiB of memory compared to 6 GiB. If you're planning at playing games at high resolutions with high-quality textures, you will need a lot of memory.
In addition, the GeForce GTX 1660 Ti has a significantly lower TDP at 120 W when compared to the GeForce GTX 1080 Ti at 250 W. Heat output doesn't match power consumption directly but, it's a good estimate.
In conclusion, all specs and GPU benchmarks considered, will recommend the GeForce GTX 1080 Ti over the GeForce GTX 1660 Ti.