Which type of case form factor is best desgined to keep a sytem cool?

The BTX is the answer the design focuses on reducing heat with better airflow and improved fans and coolers, its also gives better structural support for the motherboard than does ATX. Answer #2 = The BTX (Balanced Technology Extended) was designed to take full advantage of serial ATA, USB 2.0, and PCI Express technologies. The BTX form factor focuses on reducing heat with better designed airflow and implimenting improved colling fans and coolers.