OpenGL Performance & Performance-Per-Watt For NVIDIA GPUs From The Past 10 Years
Tesseract is one of the more interesting open-source game engine projects. The results continue to be very interesting to look at and here shows a 22x span for the tested GeForce graphics cards.
For this game the performance-per-Watt difference from the GeForce 8 to GeForce GTX 900 series is only a 10x difference.
Team Fortress 2 easily becomes CPU bound at 2560 x 1600 for the GeForce GTX 680 and faster, but at least gives some perspective for the older graphics cards.