hi. trying to buy a power supply of 450 watts or more to run a new graphics card on my pc(gateway gm5084). shopping around, the spec that seems NOT to be listed is the dimensions. my current 300 watt psu is approximately 5.5" x 5.5" x 3.25". anyone know if this is a standard or have any experience with a gm5084 that can tell me what they used? thanx!