Physical size does not matter, only the resolution of the screen. The GTX 650 Ti will perform exactly the whether it is connected to an 80" 1080p HDTV or a 14" 1080p monitor.
See below review for benchmarks which includes the GTX 650 Ti. Note there are 3 different models in the GTX 650 series: GTX 650, GTX 650 Ti and GTX 650 Ti Boost.