Dual PSU, will it work?

[Cdecker]

I'm not much of a hardware guy, so there are quite a few things I don't get about this setup.
I ordered a few new Cards and I think they will put me over the limit of my PSU (Corsair 650W) so I think I'll buy another PSU and attempt a dual PSU setup (shown here http://www.burningissues.net/how_to/power/psu.htm).

So here are my questions:

• Is there an online shop where I can buy prebuild splitters like that? I remember I once saw one on eBay
• There were a few people bringing up the problem of a power/ground differential should a card be powered from two PSUs. So am I on the safe side if I use modified PCIe risers with Molex and consistently power each Card from one PSU?
• Is there anything else to consider?

[SlaveInDebt]

Same situation here with my Corsair TX650. Its sweeting at 550w at the moment.
The adapter I have is found here http://www.frozencpu.com/cat/l3/g2/c413/s1220/list/p1/Cables-PSU_Cables-2024-Pin_Adapters-Page1.html
Not heard of grounding issues, I'll be using the TX650 to power the board +2x5850's +5750 and an oem 300w psu to push a single 5850 until a 1000+ watt psu is ordered.

[keybaud]

I believe that connecting the green wire on the PSU's motherboard connector to any of the black wires will fool the PSU into thinking that you've turned the motherboard (that isn't there) on. You can then use the PSU to power other devices as normal.

[Cdecker]

Same situation here with my Corsair TX650. Its sweeting at 550w at the moment.
The adapter I have is found here http://www.frozencpu.com/cat/l3/g2/c413/s1220/list/p1/Cables-PSU_Cables-2024-Pin_Adapters-Page1.html
Not heard of grounding issues, I'll be using the TX650 to power the board +2x5850's +5750 and an oem 300w psu to push a single 5850 until a 1000+ watt psu is ordered.

Thanks for the link, I ordered 3 right away :-)

Still the ground differential bothers me quite a lot. Anyone ever tested this? Or how are 3-4x 5970 Rigs possible?

[Nicksasa]

I believe that connecting the green wire on the PSU's motherboard connector to any of the black wires will fool the PSU into thinking that you've turned the motherboard (that isn't there) on. You can then use the PSU to power other devices as normal.

This, I've done it in the past for my folding setup.

[djex]

Same situation here with my Corsair TX650. Its sweeting at 550w at the moment.
The adapter I have is found here http://www.frozencpu.com/cat/l3/g2/c413/s1220/list/p1/Cables-PSU_Cables-2024-Pin_Adapters-Page1.html
Not heard of grounding issues, I'll be using the TX650 to power the board +2x5850's +5750 and an oem 300w psu to push a single 5850 until a 1000+ watt psu is ordered.

Thanks for the link, I ordered 3 right away :-)

Still the ground differential bothers me quite a lot. Anyone ever tested this? Or how are 3-4x 5970 Rigs possible?

I know when modding my xbox 360 to solve for the ground differential all I had to do was connect the outer metal casing of the xbox to my PC's metal case. I'm not sure if this would be the same for 2 PSU's but it might be similar.

[EpicBacon]

I believe that connecting the green wire on the PSU's motherboard connector to any of the black wires will fool the PSU into thinking that you've turned the motherboard (that isn't there) on. You can then use the PSU to power other devices as normal.

This works. I am doing it right now to power a few of my cards.