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Antec HCP 1200 12v rails

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April 27, 2012 5:12:24 PM

I'm running an i7 2600k and two 580 GTX with three hard drives and a blu-ray burner. I seen the design of the 8 12v rails. Basically what I want to know is what is the best way to power my 580s with this power supply. Should I mix different 6+2 pins from other cords on the power supply to ensure each card gets two 12v rails? Would it work like that? If I just use the same cord for both of the 6+2 pins does that mean my card is running off of one of the 12v rails only instead of the two or more?


http://www.newegg.com/Product/Product.aspx?Item=N82E168...
a c 144 ) Power supply
April 27, 2012 8:29:30 PM

oblivion666 said:
If I just use the same cord for both of the 6+2 pins does that mean my card is running off of one of the 12v rails only instead of the two or more?

Yes.

I do not know why Antec daisy chained a couple of PCIe power connectors on one cable.

I would use a separate PCI power cable for each connector. And I would try to run the CPU off a separate rail. PSU docs may tell you how to distinguish between the rails.

That may be a problem because you have 8 rails, eight PCIe power cables and a CPU power cable that must share one of those rails. Next, each rail can provide a max of 30 amps, but if you use all 8 rails together, you can only provide an average of 12.25 amps per rail (99 amps total).

This is why I favor single rail PSU's.
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a c 1167 ) Power supply
April 27, 2012 10:26:37 PM

According to JonnyGuru's review of the Antec HCP 1200 there are:

Two Fixed/Hardwired PCIe Cables are on +12V5 & +12V6

Two Modular PCIe Cables are on +12V7 & +12V8

I would recommend just using the Two Fixed/Hardwired PCIe Cables for both GeForce GTX 580 cards. One fixed cable with two PCIe connectors to one card and the other fixed cable with two connectors to the second card. There's no need to add modular PCIe cables to the cable clutter.
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a c 1167 ) Power supply
April 27, 2012 11:11:02 PM

The OCP (i.e. Over Current Protection) trip point varies between 46 to 50 Amps for each +12V rail according to another review of the Antec HCP 1200 that I've read.
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April 28, 2012 8:50:10 AM

ko888 said:
According to JonnyGuru's review of the Antec HCP 1200 there are:

Two Fixed/Hardwired PCIe Cables are on +12V5 & +12V6

Two Modular PCIe Cables are on +12V7 & +12V8

I would recommend just using the Two Fixed/Hardwired PCIe Cables for both GeForce GTX 580 cards. One fixed cable with two PCIe connectors to one card and the other fixed cable with two connectors to the second card. There's no need to add modular PCIe cables to the cable clutter.



So what you are saying is two 6+2 pins are on its own rail and there is a second set of 6+2 pins on its own rail also each being up to do 46-50 amps each rail and a 580 GTX normally needs like 20-25 amps so everything will be getting enough power and run great?

The 30 amps per rail did feel kind of low/ just minimum. I sure hope it goes up to 40 or so for each.

You know I am running a OCZ GameXStream 850W with two 580s and an i7 2600k. So many people out there tell me that you can run that setup on 850w, but that isn't true in my situation. My computer literally just shuts down because that power supply was getting maxed out only in really high end games this is why I am stepping up to a split 8 rail design with each rail having its own dedicated power.

So, someone at OCZ thought it was a great design idea for the 3rd and 4th PCIE 6+2 pins to share the same rail with the processor causing it to overload.
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a c 1167 ) Power supply
April 28, 2012 5:52:24 PM

oblivion666 wrote :

So what you are saying is two 6+2 pins are on its own rail and there is a second set of 6+2 pins on its own rail also each being up to do 46-50 amps each rail and a 580 GTX normally needs like 20-25 amps so everything will be getting enough power and run great?
Yes.

The 30 amps per rail did feel kind of low/ just minimum. I sure hope it goes up to 40 or so for each.
In the review I read, where they tested the OCP trip point for the +12V rails, they made a comment that they thought the OCP trip point setting of 46 to 50 Amps is set too high so I think you'll have no problems in that respect.

You know I am running a OCZ GameXStream 850W with two 580s and an i7 2600k. So many people out there tell me that you can run that setup on 850w, but that isn't true in my situation. My computer literally just shuts down because that power supply was getting maxed out only in really high end games this is why I am stepping up to a split 8 rail design with each rail having its own dedicated power.
On the OCZ GameXStream 850W (OCZ850GXS) power supply's label and any of its documentation they never specify its combined +12 Volt continuous current rating. That should raise a red flag because hiding such an important spec would indicate some deficiency that is being hidden. My calculations indicate that it is 60 Amps or less which is insufficient for two GeForce GTX 580 in 2-way SLI mode. A power supply should be purchased based on its combined +12 Volt continuous current rating and not based on its total wattage.

So, someone at OCZ thought it was a great design idea for the 3rd and 4th PCIE 6+2 pins to share the same rail with the processor causing it to overload.
Actually the design and manufacturing (i.e. OEM) of the OCZ GameXStream 850W (OCZ850GXS) is done by FSP so blame them. OCZ only gets to specify the FSP platform to use and such things as paint color, component quality and cable lengths. That design decision, that FSP made, doesn't meet the ATX12V Power Supply Design requirement that the +12V rail(s) for CPU power must be separate from the +12V rails for the other components.
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April 30, 2012 12:15:03 AM

Great I have it installed already. Don't you just LOVE IT when you buy something and literally 24 hours after you buy it newegg puts out a promo to get 15 percent off a 300 dollar power supply?

Thanks for making me feel bad newegg
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May 17, 2012 4:30:00 PM

Best answer selected by oblivion666.
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