| With the BAT design the processor socket is located at the front of the motherboard, and full-length expansion cards are intended to extend over it. This means that removing the processor requires the removal of some or all expansion cards first. Problems were exacerbated by the increasing speeds of Pentium-class processors. System cooling relied on the AT power supply blowing air out of the chassis enclosure and, due to the distance between the power supply and the CPU, an additional chassis fan or active heatsink became a necessity to maintain good airflow across the CPU. AT power supplies only provide 12V and 5V outputs to the motherboard, requiring additional regulators on the motherboard if 3.3V components (PCI cards or CPUs) are used. |