So how big is it really? Plus what does it power? Also is it modular and does it have a 135mm fan or something else? Mine was a Silverstone 650W ST65ZF-GM (non-modular) and it powered: a dual CPU s771 mobo 2 Xeon E5320 CPUs 4 FB-DIMMs 1GB each 8600GT video card 2 SATA HDDs 3 fans (120mm x 2 and 92mm) PCI-e soundcard Estimated power consumption 300W 1 fan at the rear and it was LOUD! That's it nothing else. Well until it broke and now I use a 500W Nexus PSU (non-modular), very quiet. So what powers your computers? If multiple choose the highest rated PSU.