I have an NZXT Lexa S case, the PSU sits at the bottom of the case. Which way up does the PSU go exactly, because I think I may have mounted mine upside-down. At the moment I have mounted mine so that the fan is pointing upwards towards the graphics card, should it be so that the fan is facing the floor? I have a dust filter on my case right underneath where my PSU sits and that's why I think I have mounted mine in upside-down.