[saq]

4xR10k will take about as much as 4xR4400, so don't worry about it. Indigo2 required a different PSU because the draw off of different rails was different, but Everest machines (Onyx/Challenge) have the final regulators on the boards.

I used to have a CHALLENGE L and ran it off of a 15A/120V outlet. Not best practice, but... All EBUS slots were filled in that baby.
Currently run a loaded O2000 off of the same outlet.

I believe the power requirements jump up to 220 with 2 RMs, but if you were to leave the VME unloaded and only have one or two modern 1/3 height drives instead of the type that were around when Onyx was made you MIGHT be able to get by on 120.

Rack machines with the third card cage can have 3 phase power, but anything under that is single phase. Pretty sure it is convertible anyway, not like the big VAXes where the blowers were 3 phase.

[Raion]

So just a little aside here but:

I run 2RM10s (IR3), 4 400MHz R12ks and 4G of RAM on a 20A circuit for my onyx2 successfully at 120V.

Just saying, I think that it's a bunch of bunk that you can only use one RM or something like that.

[jan-jaap]

That's an Onyx2.

I think I measured my Onyx2 with 4x500MHz CPUs, full RAM, misc options and dual RM10's running full-blast at ~ 950W once, and my Onyx at ~ 1500W, and I think that was with only one RM. No idea about surges at power-on. Both at 230 VAC.

There's a some room to maneuver between "company XYZ certifies that this will work safely" and "it might work without burning your house down, but hey you wouldn't let it run unattended anyway". But I wouldn't push it. Personally, I have two dedicated 230VAC groups with slow fuses in my computer room, plus a third for lights etc. My limitation is not how to get enough power into the room, but how to get all the heat out again ...

[Irinikus]

It's good do see that the Onyx2's power supply has loads of headroom then! As 950W is nowhere near its max rating!

Luckily for me, all of my outlets are 220V@50HZ!!!

I do agree getting heat out of the room is a problem, especially down here in Southern Africa!

The machine in my collection which throws the most heat is without a doubt the Sun Fire V880Z! The Onyx2 and the Tezro don't do too badly themselves though!