Phoronix published NVIDIA GeForce GTX 680 To RTX 2080 Ti Graphics/Compute Performance (GTX 680, 780 Ti, 980 Ti, 1080 Ti, 2080 Ti) under Linux A quote from the article:

Yesterday were the initial NVIDIA GeForce RTX 2080 Ti Linux benchmarks based upon my early testing of this high-end Turing graphics card paired with their new 410 Linux graphics driver. For your viewing pleasure today is a look at how the RTX 2080 Ti compares to the top-end cards going back to Kepler... Or, simply put, it's the GeForce GTX 680 vs. GTX 780 Ti vs. 980 Ti vs. 1080 Ti vs. 2080 Ti comparison with OpenGL and Vulkan graphics tests as well as some initial OpenCL / CUDA tests but more Turing GPU compute tests are currently being conducted. For making this historical comparison more interesting are also power consumption and performance-per-Watt metrics.

 NVIDIA GeForce GTX 680 To RTX 2080 Ti Graphics/Compute Performance (GTX 680, 780 Ti, 980 Ti, 1080 Ti, 2080 Ti)