Quote from: robix on June 18, 2013, 08:57:44 AM

Quote from: BenTuras on June 18, 2013, 07:33:46 AM

Quote from: robix on June 18, 2013, 07:09:40 AM

I'm planning to make stacks of 12 boards. I've chosen a OCZ ZX850W PSU. It's a single rail with max. 70A at +12V. It has 4 PCI-e connectors, so I can connect to 4 boards. From each of this boards I'll daisy chain to 2 other boards by the terminal block. Power should be sufficient. The PSU should operate in its efficient range, and the current on the single wires is not too high.

Your solution indicates a much higher current than the 75W for a PCI cable. Is that OK ?

I don't know if there's a limitation to 75W per PCI-e cable. In my case there would be ~120W per wiring. Do you have a source for the 75W limitation? I'll look into the PSU reference guide.

That is the reference design, yes.

You have 75w per PCI-e 6 pin cable. Since The GPUs became just too insanely power hungry with time the 8 pin was added. An 8 pin pci-e plug brings 150w, a 6 pin brings 75w maximum.

Therefore, the maximum power a GPU can take is 75+150+150 = 375w at the moment.

Additional to that, you will find that burnin has one of these nice green block adapter solutions on the board. That means that from my point of view, you can use EVERY single of these yellow 12v variations to power a SINGLE board:

You just need to use either an adapter or cut it off, crimp it and then connect it to a board. Remember that there is a maximum power draw per module on the PSU though. Theoretically you daisy chain 700w off from ONE module, but this build will surely make you meet a fire extinguisher scenario...

In the ideal scenario, you put as little as possible on every line and have one module for every board. The 8 Pin PCI-e should be able to take 2-3 boards though.