. Delta has gone almost strictly OEM, so you seldom see them in the retail channel. People without long perspective of the computer market wouldn't know that Delta is a top PSU maker - right up there with Channel Well (makes Antec, Enermax, et al.) or Enhance (makes Silverstone PSUs, et al.) HP wouldn't put it in workstation level products if it wasn't quality goods.
. If it really is a dual-Xeon PSU, then the first 20-pins pinout would be the same as ATX and the 24-pin pinout would be the same as the EPS-12V standard , but I'm thinking that the X4000 could be dual AMD too so the pinout may not be the same. I think it may lack the P4-12V (4-pin square) but if it is dual Xeon, it should have an 8-pin connector that is 4x12V and 4xGround that would also work but hang over the sides of the 4-pin mobo socket so you'll need some clearance around it ditto with the ATX - if you don't have clearance off the end of your 20-pin ATX connector and /or the P4-12V, then you'd need to use an adapter (which isn't ideal in high-current circuits). Best if an adapter(s) is necessary is to pull the pins you need and put them in the proper shell - being VERY careful as to the pinout. Places like SVC.com, FrozenCPU, jab-tech, et al. have shells (in UV colors!!!) and pin removal tools that would end up costing less than an adapter(s).
. Make sure by asking the seller before buying. HP is still selling those PSUs for $150. new - so it is a steal! I'd also like to know the Amps on the Rails - looks pretty good, but the pic of the label is hard to read for me.
.bh.