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Help - Very confused about PSU and 12 V Rails

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April 20, 2012 12:01:10 PM

Hello,

Yesterday I finished assembling my new computer with this components:

Seasonic M12II 620W (one of the recommended ones here at tomshardware)
Maximus iV Gene - z/Gen 3 motherboard
i5 2500 k
Corsair Vengeance 1.5 V 1600 MHZ (4 x 4 gb) 16 GB
Western Digital Blue 500 GB Sata 3 6GB
Asus DVD
Saphire HD 7850 OC edition
NZXT Guardian 921 Case

Everything is working perfectly fine, however I haven't really put the system into stress yet.

I believe everything is correctly connected but wanted to check, since my Seasonic does not come with any useful instructions about where the "rails" are, it only lists how many it has and the A in each of them.

This is how I connected everything please let me know if it is ok:

1) One of the non-modular Cables the 24 Pin one went into the motherboard
2) One of the non-modular Cables with 8 Pin (that do not split, because there's another non-modular that does split into 4 - 4), this one went into the CPU (the other one that does split doesn't fit anyway so pretty sure this is correct)
3) On the modulars I connected one of the SATA powers that went to the Hard dRIVE
4) On the modulars I connected another SATA (because even though each sata has 3, it wouldn't reach to connect both), this one went to the DVD
5) On the modulars I connected one of those cables with 4 pins to power up fans
6) On the modulars, I had to connect another of those cables with 4 pins to power up the power led and some lights
7) Finally on the bottom there are 2 modulars for 6 pin PCI Express, I connected it on the first one (from top to bottom), and powered my HD 7850 with it.

Other notes:

1) The Video Card went of course to the PCI Express connector in the Single @x16

One note the modulars do not have any kind of labels, so I just plugged them randomly on the PSU, does this matter?.

I am just confused as to where are this "rails"??. Particularly my question is my PSU has 2 +12 V rails each one at 24 A, do I have to do anything to combine them, to give my Video Card the combined 48 A?.

Any help will be greatly appreciated!.

Thank you,

Oscar

EDIT: Other notes I was able to play Starcraft II just fine for 30 minutes yesterday.

More about : confused psu rails

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a b ) Power supply
April 20, 2012 12:25:26 PM

what you really have is one 12v rail that has been split

each split delivers 24a if needed and most likely one split power the CPU while the other split power the mobo, hdd, video card. your video card won't ever need 48a, i doubt it needs more then 10-12a at load.

more info on the subject for your leisure reading
http://www.jonnyguru.com/forums/showthread.php?t=3990

modular cables should connect as such



FYI, hardwaresecrets states that platform is actually a single rail design which corresponds with all the other brands out there that use that platform for their builds.

http://www.hardwaresecrets.com/article/Seasonic-S12II-B...

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a c 144 ) Power supply
April 20, 2012 12:56:45 PM

dirtyferret said:

each split delivers 24a if needed and most likely one split power the CPU while the other split power the mobo, hdd, video card. your video card won't ever need 48a, i doubt it needs more then 10-12a at load.

The SS 620 is a semi-modular design. The high power cables are fixed. dirtyferret is right. One rail is internally wired to the main power cable and modulars. The other is connected to both CPU power plugs (you will only use one).

For its performance, the 7850 is a pretty efficient card. Again, dirtyferret is right. At load, the 7850 won't pull more than 12 amps. I estimate total system load at around 320 watts, certainly no more than 350 watts.

You have plenty of power for your system.
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a b ) Power supply
April 20, 2012 2:00:20 PM

^ both posts are excellent.
You said " to give my Video Card the combined 48 A". Your Video card will NOT take anywheres near that ( 12 x 48 = 576 Watts) where that comes from is what the typical system needs when using a LOW end PSU.
As JSC stated Your power will be less than 350 Watts total for the COMPLETE system.
My i5-2500k OCed to 4.2 GHz, w/ATI 6870, 16 Gigs ram, 4 drives draws right at 350 Watts measured at the wall outlet.
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April 20, 2012 2:19:23 PM

Wow, thank you all for all the great and prompt responses. Looks like everything is ok then, as per the diagram you can plug the Sata and Molex wherever you want. Also I have enough power =).

One more question that isn't related - my motherboard has 2 x PCIe3.0/2.0 x16 slots (Single @x16 or dual @x8/x8 mode) with NVIDIA SLI/ AMD CrossFireX support, from what I understand this means that if I only use one port it will run at x16 and if I use both then they will both run at x8 correct?.

If I am using only a single PCI E port, does it matter to which port do I connect to?, I currently connected it to the one closer to the CPU.
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April 20, 2012 2:19:50 PM

Best answer selected by oscarmk.
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a b ) Power supply
April 20, 2012 2:57:29 PM

Yes, one GPU = X16, 2 GPU = x8/x8 Note the there is NOT a big diff between X16/X16 and x8/x8.
With single GPU, I believe the prefered slot is the top one (closes to the CPU).
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a b ) Power supply
April 20, 2012 7:09:14 PM

RetiredChief said:
Yes, one GPU = X16, 2 GPU = x8/x8 Note the there is NOT a big diff between X16/X16 and x8/x8.
With single GPU, I believe the prefered slot is the top one (closes to the CPU).


+1, most mobo manufactures prefer you to place the card in top PCI-E x16 slot (closest to the CPU)
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a b ) Power supply
April 20, 2012 7:43:50 PM

This topic has been closed by Mousemonkey
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