Hello... here is a Wiki definition... http://en.wikipedia.org/wiki/ATX so as you see in Power Supplies the various types and sizes. In MB's uATX and ATX have Standard mounting dimensions and holes for each type... Typically a uATX and ATX MB will fit in the same ATX case... But not a ATX mb in a uATX case.
Hello... here is a Wiki definition... http://en.wikipedia.org/wiki/ATX so as you see in Power Supplies the various types and sizes. In MB's uATX and ATX have Standard mounting dimensions and holes for each type... Typically a uATX and ATX MB will fit in the same ATX case... But not a ATX mb in a uATX case.