I know that there are 2 types of PSU, ATX and mATX. The current one I have is a "FSP250-60HCN" supply which I am upgrading to a EVGA Supernova 750w B2, which I know is a ATX. However my current one only just about fits my case, and I'm worried when the new one arrives, it'll be too big When searching online, I couldn't find any anything on which type the old one is, can anyone help?