The DeepCool Steam Castle has a the Micro-ATX form factor. Micro-ATX is a smaller version of the ATX standard which is designed to make your case and the system therein lightweight and portable. Using the Micro-ATX standard, the case can house motherboards and power supplies with form factors Micro-ATX and Mini-ITX. The dimensions of the case itself (LxWxH) are 406mm x 278mm x 420mm.

The DeepCool Steam Castle has four expansion slots, so there is some room for extra components, which may be a deciding factor when planning on the longevity and build type of a PC system. The case has one 5.25" drive bays, which is enough room for an optical drive but little else, and with just one 3.5" drive bay, there is basically no room at all for expansion. With two 2.5" bays, however, there is enough room for a laptop-sized HDD or solid-state drive. Installation of hard drives into these drive bays is made all the more easier by screwless rails that allow tool-less mounting.

Made primarily of Plastic, the DeepCool Steam Castle is built to be lightweight, but strong enough to keep your components protected. Plastic cases generally have a thin metal layer to improve protection, and are also generally fairily cheap. Whatever your case's material, it is important to keep a consistent airflow so that heat doesn't build up inside. It is therefore advised that you make use of the available built-in case fans and fan installation sections.