SLI power connections

[geneticmaterial]

Hi
I have two Zotac GTX970 cards in SLI
They both have 2 6 pin power connections.

I run these from a corsair cx750m.
I have 2 pci power cables, each goes from 1 6pin at the psu and has two 6pin connectors inline / in sequence.

Now my question is;
should I have each rail for each card - using both of the 6 pin outputs on one card?
OR
should I run each rail to run both cards - using one of the 6pin outputs on the bottom card (as that's first from my psu) and then the 2nd inline / in series 6 pin connector to the second card.

I have run the cards both ways and I can't tell the difference.

I haven't yet managed to game using the second option so they haven't had chance to draw much power in that configuration.

I've never SLI'd before and not sure if these power connection differences matter?

The reason for asking is that option two is far neater in my configuration.

Hope that makes sense

Dan

OPTION 1

OPTION 2

 

[WesleyBurns]

Rail for each card

 

[ubersonic]

Option one

 

[geneticmaterial]

Thanks for the responses. Can you explain why?

 

[murah]

got the same PSU as you modular version, top card has the first PCI-E power connector bottom GPU has the other one.. failing to see the issue here..

 

[Fleshwerk]

Do you get any coil whine? I have the same psu as you.

 

[geneticmaterial]

Yeah, I can't see what the difference would be either.
either way, one of the slots on either of the cards will be 1st or 2nd in line on the rail.
Unless it impacts load balancing on the two rails, but I would have thought that the cards will be working using the same power consumption as they are in SLI.

 

[geneticmaterial]

I haven't really noticed any whine with the sound of the gunfire and engine noise lol. I'll have a listen

 

[geneticmaterial]

Hi,
my audio went absolutely haywire last night; crackling, juddering and a lot of white noise and then working normally. There's no pattern to this and this was across all sources (web, spotify etc).
I tried enabling and disabling loads of stuff, even network drivers as suggested on one forum. Reboots, restarts to no avail. Nothing worked.


I then remembered to check the "whine" as mentioned above.

Now the PSU makes an off on random buzzy whine, which can only be heard when the fans are set to "silent" and only when I get myself down to the PSU can I hear it.
However, when the psu is buzzing, the audio is clear and works, it's when the buzzing stops that the audio goes all notchy.

Now between my diagnostics and me listening to the PSU, I RMA the motherboard and it was accepted. Now I'm thinking get rid of the PSU.

update;
I originally had the PSU inline with my three monitor on one extension cable that goes straight to the wall outlet.

I have moved the PSU plug directly into the wall, solo. The PSU now has the buzz whine constantly but the this means the audio is clear.

Strange.