Hello, I was confused about something so I was wandering if anyone can help me out. Basically I have an OCZ 550W Fatal1ty PSu and whilst I don't have an issue with it, I was wandering something about the advertised amperage ratings. On the side of the PSU it says that there are 2 12V rails, each with a rating of 25 amps with a total advertised output of 450W (The other 100W is for the 5V and 3V rail). Is that not off? If I use the equation: power = voltage X current I get 12 volts X 25 amps = 300W per rail. So 600W for both rails no? I ask because Corsairs TX650 has 52 amps on a single 12V rail and is rated for 624W of output. Also I want to know what flexibility I have in terms of adding a decent graphics card (my one has been RMAd). I mean 150W is quite a big difference and will allow me a lot of breathing room. It may even be a misprint.