Which type of motherboard is primarily designed for smaller and more portable systems?

The motherboard type primarily designed for smaller and more portable systems is ITX. ITX, or Integrated Technology eXtended, motherboards have a compact form factor, making them ideal for use in small form factor (SFF) builds, laptops, and compact desktop systems. Their design allows them to fit into tighter spaces, facilitating the creation of lightweight and portable computing devices.

In contrast, ATX motherboards are larger and designed for full-sized desktop systems, offering more expansion slots and connectors but at the cost of portability. MicroATX motherboards, while smaller than standard ATX, are still not as compact as ITX and are often used in mid-range desktops where some expansion capability is desired. Server motherboards typically cater to enterprise needs and may have a larger form factor to accommodate multiple processors and extensive connectivity, which doesn't align with portability concerns.