Hi - What is the brand/model of your PSU? I suspect you probably don't have a good enough PSU
to power that system. However, list the PSU brand/model in order to find out one way or another.
Ha, yes, I ended up pulling it out to find it's only 450W, leaving me a bit short, thought I'd had a 500W. One overcompensating trip to a part store later and the problem is solved in a new 750W with all kinds of neato connections.
Would still be interested to know if, assuming the supply had the wattage required in the first place, that would have worked.