Prepare the macaroni as per package instructions, then drain.
In a large bowl, combine the shredded cheddar, cream cheese, milk, sour cream, melted butter, salt, black pepper, and garlic powder.
Add the drained macaroni to the cheese mixture, stirring gently until fully combined.
Transfer the combined mixture into the crockpot, spreading it out evenly.
Cover and cook on low for 2-3 hours, or until the cheese is melted and bubbly.
Stir the mac and cheese halfway through cooking for even consistency.
Once cooked, let it rest for about 10-15 minutes before serving.