I am planning on buying a UPS for my computer soon. The only thing im confused on, is which one is right for me. When it says its a 540W UPS, does that mean, my power supply in the computer has to be 540 watts or less, for the UPS to power my computer? Can someone explain this. In my computer I have now, I have 300 watt power supply, but most likely going to put a 400 to a 500 watt power supply in it, once I order my 6800 GT.