You will die. Frequently.
You will stare at your screen as it slows to a crawl, wondering when the whole machine will just black out and die.
You will roll your eyes and groan as if somebody just cut you in line at the grocery store and you want to get their attention in an obnoxious, passive-aggressive way.
You will eventually turn off Diablo III and find something less stressful to do, like operating a push-powered forklift or jumping up a cliff.
See, running Blizzard's latest action-RPG on an awful graphics card is like playing blackjack at a casino; it might be exciting and even euphoric for a while, but sooner or later you know you're going to lose everything.
A few years ago, I bought a Samsung Q430 laptop. It's a wonderful machine: not too heavy, fast enough, and sleek in all the right places. But it's saddled with a NVIDIA 310M graphics card, the type of entry-level hardware that can barely run Minesweeper, let alone Diablo III. (This is an exaggeration. My computer can run Minesweeper at phenomenal frame rates.)
This setup was okay for a while, mostly because I could browse the Internet and play StarCraft II. But then Diablo III came along. And with it came those old familiar cravings.
I wanted to hunt for glorious loot. I wanted to beat up Mephisto. I wanted to see what happened to Deckard Cain. I wanted to discover new bosses and dungeons and towns and all the other cool shit that Blizzard packs into its games, which are almost always awesome.
So I ignored the little voice in my head that said "your computer can't run this, dumbass" and started installing Diablo III. Roughly ten thousand hours later, I loaded up the game, ignoring the little message on my computer screen that said "I can't run this, dumbass."
And! It worked! The game loaded up smoothly. I entered my Battle.net information. I connected to the Internet. I created a Barbarian. I immediately skipped the opening cinematic for fear of angering the Graphics Gods. I entered the game and started moving around my character, tempted to brag on Twitter about how awesome I was. I had done it! I beat my own graphics card! It worked! I'm a champion!
Then the game froze.
See, the problem with running Diablo III on a crappy graphics card isn't that it won't work. It'll work. The problem is that whenever too many enemies appear on the screen, or some sort of dungeon animation requires a lot of processing power, your computer will suddenly start skipping like an awful dubstep producer.
Every minute or two, everything will go through a time warp. You will watch enemies surround your helpless character, who apparently lacks any sort of life-preservation instincts whatsoever. You will frantically click away from enemies. It won't work. You will frantically slam Q on your keyboard, trying to chug down a potion. It won't work. Your roommate will ask why you are clicking so much. You will ask why he hasn't done the dishes in three weeks. You're in a bad mood. You'll apologize later.
Still, you'll make it through a good chunk of the game thanks to some careful timing (and the fact that death doesn't penalize you until you reach level 10). Until you get to the game's first boss, Leoric the Skeleton King. He will immediately drive your laptop into conniptions. You will die. You will die again. You will give up, shut down the game, and watch basketball for a little while.
And you will order a new computer.