Desktop monitors (I'm not talking laptops except for the high-end laptops) tend to vary in size from 20 to 24 inches for mainstream/standard monitors, and 27 to 30 inches for the high end. One thing they all have in common is the resolution. They have pretty much standardized on 1920x1080. That's because 1920x1080 is the resolution for HDTV, and it fits 20 to 24-inch monitors well. Here's the thing: at that resolution, these new GPUs are so powerful you get no major, appreciable gain over the older generation.
Or as Chris Angelini, editorial director for Tom's Hardware Guide, put it, 'The current high-end of GPUs gives you as much as you'd need for an enjoyable experience. Beyond that and it's not like you will get nothing, it's just that you will notice less benefit.'