Do you want to know how you can tell the biggest difference in resolution?
1. Open a game like, say, BioShock Infinite on PC (it has to be a game with horizontal live bars). 2. Set the resolution to 1920x1080 and run around for a few minutes. 3. Close the game and re-open it. 4. Set the resolution to 1440x900 and run around for a few minutes. 5. Close the game and re-open it. 6. Set the resolution to 1280x720 and run around for a few minutes.
All throughout this process, pay attention to the life bars and the edges of the screen.
At 1920x1080, the life bars will take up a couple of inches, if that, in the upper left corner, and your field of view will be sort of bad. (You need to set it to 90 degrees in the options, but they made it a screwy setting so you have to look up what number to put in for 90).
At 1440x900, the life bars will be slightly larger, and you'll notice that you can't see as much at the edges of your view.
At 1280x720, the life bars are gigantic, and you'll notice even more of an increase in vision.
It's not about sharpness per se, though that is part of it. Your field of view is drastically decreased as resolution gets lower.
I've seen YouTube videos of BioShock Infinite on the consoles and the life bars take up almost half the screen, it's pretty ridiculous.
lol dude you don't need a game to know this, that's what resolution does
you can just change the resolution on your computer screen right now and see the difference