Hi - just seen this thread.
As RDC alluded to - I got one of these a few days ago and can confirm that in it's factory form, it is IMO a pretty bad product.
It doesn't matter how many 'rails' your ATX PSU has, this product does NOT use the main ATX power rails (for the DVD, HDD drives etc, nor does it use the ATX PC 12v connector). It uses the 12v connector on the main 20/24 Pin ATX motherboard connector only ...

This connector was never designed for high current loads, for one, there is only a single connector compared to the multiple 3.3v and 5v connectors on that block - that tells you that it light load 12v only - probably 2-3A tops.
Inside the official xbox360 lead and the Energiser one are 6 primary power wires, 3 yellow, 3 black. These are 20 AWG(ish) and so can take about 6A EACH. Therefore, they use 3 to increase the load without having a bigger but less flesible power cord. 3 x 6 = 18A.
Now for the official 360, EACH wire terminates onto a decent heavy duty contact - providing a high current solution.
The energiser on the other hand terminates all 3 yellow wires onto ONE small light duty contact and the other 3 black wires onto another small light duty contact ... Hmmm, I don't think so ... Did they not learn the lessons from the 'Intercooler' fiasco on burnt up contacts - heavy current = arcing of contacts unless they are decent quality and designed for the load in question. This contact is clearly not ...
I'm waiting for a decent PSU to turn up before I can experiment further, but for the moment don't expect this product to work with the majority of PSU's... Maybe clever ones that can shuffle power around as required...
BUT
I'm very concerned about that single wire from the PSU taking all that current - it's gonna get warm - so watch it like a hawk ...
Some Pics of progress so far ...
20/24 Pin ATX Connector :-
Shield on cable :-

Split cable :-

Update soon ...
Cheers, Richard.
This post has been edited by RBJTech: Mar 3 2007, 11:47 AM