It's not about size, it's about application. Server boards have RAM slots front to back, and workstation boards have them bottom to top. For good reason. And I've heard of W chips working in server boards. They're not guaranteed to work, and firmware updates may break them working. Intel used to have no distinction. For instance, I have an X11SRM-F and W-2140b in my desktop. When they came out with the W-31xx is when they REALLY started forcing segmentation between servers and workstations. Making vendors make server boards that supported ONLY server chips, and workstation boards supporting both. For some reason they allow both on workstations. And as for boot times, I don't know about their workstation boards, but the server boards take forever.