The BTX motherboard form factor is slightly larger than that of ATX (325x266mm vs 305x244mm). BTX motherboards were designed to place the CPU towards the front of the case for better airflow. BTX...
For the most part it's size, and AT is very old computer wise. See here for more detail: http://www.devhardware.com/forums/motherboards-32/at-vs-atx-179846.html
AT mother board is having an SMPS of mechanical swtich, where as the ATX, other board has an SMPS with DC switch (automatic). This is the main difference.AT mother board is having an SMPS of...
AT mother board is having an SMPS of mechanical swtich, where as the ATX, other board has an SMPS with DC switch (automatic). This is the main difference.