Two lower-end powersupplies going to one rig?

[nightminer]

Hi Guys

I've been reading and looking at other miner setups, and I never noticed anyone using 2 lower-end powersupplies. They always use one 1200W power supply to drive 3 cards. In my country these PSU's seem to come at a premium (they know that they can push the price for anyone wanting that much power).

I could get 1200W from two 600W bronze 80+ rated PSU's for half the price of one 1200W bronze 80+ PSU.

Is this recommended? Can I run the motherboard off one PSU and then run the graphics cards off the other PSU? Would it even turn on without it getting a "power on" signal from the motherboard?

[andybird123]

yes you can, you just need to use a jumper of some kind to trick the 2nd PSU in to coming online
I have this setup on mine at the moment for similar reasons, I managed to find an extension cable that piggy backs off the main motherboard lead and starts both PSU's together, but you can just use a piece of wire or a paperclip to do it manually (you just need to use the switch on the 2nd PSU itself just before you start the PC if doing it this way)

[lbr]

Simple anwser - don't do it ; )
Search web why it is not adviced.

Though, last time I've tried, worked for me.

[Punkonjunk]

I actually had a lot of trouble finding an article or write up as to why NOT. The first search got me a whole bunch of stuff about lightbulbs for growin' drugs.
The second still didn't have anything useful over several pages, but I'd love some information here as to why not! I can only imagine problems if you mounted them both inside a case, and didn't consider the cooling needs.

EDIT:
Found a good write-up:
http://www.overclock.net/t/1177714/faq-dual-power-supplies

But with little sources or technical reason besides obvious stuff.

What is made clear though, is it probably isn't that bad an idea if you're using it for more GPU rails, and I can't find anything contesting this.

It's a nice cost saving technique I'd love to be talked out of!

[nightminer]

Thank you guys

I also did some searches myself and also could not find any people saying it's a bad thing. One guy even said he's been doing it for years because he prefers his fan spinning after his PC shuts down. He ran all his DVD drives and extra HD's off it as well. He did this with very cheap 300W powersupplies laying around and said he never had any power spike problems or anything else.

But now the million dollar question - it's one thing to run a few HD's and fans like this, quite another to run your 2 power hungry GPU's off it.