Sites like Newegg have their very own energy provide calculators, with various degrees of complexity relying on how far down this particular rabbit hole you need to bounce. Generally talking, 300W will run a desktop without a GPU, 550W will handle a midrange GPU or below, and a high-end GPU wants no less than 600 watts. The difference between an ATX Full Tower and an ATX mini tower, if each support a full-sized ATX motherboard, will be the height and clearance within the case itself. Your GPU and cooler options may be constrained when you go for a small tower, even if the motherboard itself always suits into the available space. As you shop for a case, you’ll see them labeled “ATX Full Tower,” “ATX Mid-Tower,” and so on. Any chassis labeled ATXshould be capable of dealing with a full-size ATX motherboard.