I always seem to have the right power supply, but this time I don't. For a pc I'm building I need a 400w power supply. Now you may be wondering "but 21, those are easy to find!" Well here is the catch, I need a very small one. In fact the dimensions can't exceed 80(H) - 40(W) -220(L). After hours on the internet I've come across some candidates but they are just barley to big. So any help is greatly appreciated.