Difference AT and ATX Power Supply are:

1.With ATX Power Suplay we can shut down the computer through the operating system because the power on / offNya controlled by the motherboard while the PS AT must be done manually via a button / switch

2.Besides the PS type AT power cable to the motherboard separately with Pin 8 and Pin 9.

3.In Type ATX, the connector from the PS to the motherboard are not separate (one connector).

For the current ATX power supply connector type pin con-24 are more widely used

The following pictures ATdan ATX connector :