This is a critical advantage in the computer industry, where component costs account for 75 percent of revenues and typically fall by 1 percent per week due to rapid obsolescence. For example, when larger, faster hard drives are introduced, which occurs every three to six months, the value of previous-generation hard drives is significantly reduced. So if Dell holds one week of inventory, and a competitor holds four weeks; this translates immediately into 3 percent worth of component cost advantage to Dell, which can mean a 2 percent advantage on the bottom line. Driving inventory out of the system also dramatically reduces Dell's need for working capital and boosts the company's profitability.