Run pico psu from a pci-e power line

[JonJ678]

Hey guys. The idea seems basic, but I haven't seen it done. Say I have a normal desktop computer, and a mini itx system. I want to run both at once.

The pci psu takes 12V dc from a transformer and splits it up as required by the motherboard and peripherals.

Graphics cards run off 12V DC.

Can I therefore directly wire the 12V pins on a pci-e power cable together, and the 0V pins together, and use these two cables to run a pico psu block?

Obviously the mini-itx system wouldn't work with the main one turned off. I'm relying on the idea that whenever the atx psu is on it offers a steady 12V across its pci-e contacts, and continues to do so regardless of load until the computer is powered down. I don't suppose anyone knows if this is maintained during reboots?

It's also an issue that forgetting to turn the mini itx system off would lead to it suffering many hard resets. Can anyone offer more detail on the specifics of this?

 

[NightmareXX]

Not really knowing much about electrics but it sounds like it would work. As far as I'm aware, a PSU provides power to it's rails until the main motherboard is turned off so yes, as long as the main PC was on you could run a pico off the graphics card power line.

As for rebooting, I'm pretty sure the power is provided across the rails as you'd expect.

 

[Col_M]

The only thing I'd be concerned about is if the PSU can provide enough current and therefore power.
But considering that some graphics cards can use 90W+ and your average m-ITX system can use as little as 50W at full load I think you may be ok.

Worth a try

 

[JonJ678]

Looking like good odds then, cheers. I'll try to find out some more electrical specs before attempting this, expect an update in 6 to 8 months :s

Cheers