One ATX PSU to power supply two motherboards:: is it possible?

[0db]

I am thinking about building a computer with two motherboards in one small cabinet; each motherboard needs neither hard-drive nor GPU, just need a lot of ram (>=4Gbyte) for the ram-disk and a fast LAN (>=1Gbs) to bootstrap from the network.

Peripherals are not a problem, motherboards are in m-ATX form factor, both equipped with Intel Core2 Quad Q9650 chip @ 2.9Ghz, and each board doesn't eat more than 150 Watt.

I can build the special cabinet myself, just .. what about the PSU sub section? Can I use one single big 500 Watt main power supply to feed both motherboards?

In case, if it's possible, is there any kit/cable/something to do so?

Thanks 

[magic]

Interesting question.

I'm not aware of this having been done and I doubt there are kits. You will probably need to DIY an ATX connector splitter.

Turning on one board will apply power also to the other. I'm almost 100% sure that it won't cause it to actually start running, what the exact effects will be I don't know. It ought to be harmless, I think.

edit
A less unorthodox solution is to use some beefy 12V-only supply (possibly even ATX) and a pico-PSU for each board.

[sleemanj]

Atx 24pin splitter (Y) cables appear readily available (don't forget you might also need to split the smaller cpu, gfx power connectors etc if your psu doesn't have enough of those).  I think you would want to lift and hard wire ps_on to ground to force the supply to be always on, otherwise it would depend on how each motherboard implemented the ps_on signalling (in regards to if it pulls up/down hard or with some resistance or leaves the off state as open circuit)

[magic]

I always assumed that PS_ON is open collector and could be safely connected in parallel, but now I'm not sure how to read that wording in the spec.
https://www.manualslib.com/manual/77829/Intel-Atx-0-9.html?page=17

Certainly no harm in testing the boards in question before connecting them.

[LeonR]

If you lack space there's always TFX/SFX PSUs (Ebays and alike have a lot of Seasonc branded models).

[Ralf_CT]

Why not just use a dual-CPU server board?

[0db]

Because I need independent I/O subsystems, thus two independent motherboards.

Solved with two mini PSUs, 200Watt each, installed into a custom cabinet