Despite tepid reviews, demand has exceeded supply for Valve's quiet but underpowered Steam Machine, leading to waitlists in many regions. If you're in the reservation queue or on the waitlist, Valve has provided clear information on what to expect. "For everyone receiving a purchase email: You must complete your purchase within 72 hours or we will move to the next person in line," Valve said. As part of the announcement, Valve also unveiled two Steam Machine updates. And if you want to build your own Steam Machine accessories, its CAD file is now available for download here.