The Dell percision T3400 has a the ATX form factor. ATX is the most ubiquitous of case standards, providing the largest array of compatible hardware on the market. Using the ATX standard, the case can house motherboards and power supplies with form factors Array. The dimensions of the case itself (LxWxH) are 468mm x 171mm x 447mm.

The Dell percision T3400 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. There is also no 2.5" drive bay for a laptop-sized HDD or solid-state drive.

Made primarily of Steel, the Dell percision T3400 is built to be strong and well-ventilated. Steel cases are generally fairly cheap and sturdy, but also tend to be quite heavy. 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.