Wondering about PSUs, rails, amperage, etc

Hardware Hub PSU
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Just from what I have read, that it is best to avoid PSU with multiple rails. However, looking at some 750w supplies, I can see that most seem to have 2 - 4 rails.

And here are some examples, as these are PSU I have looked at recently:

FSP Aurum 750w, 80plus Gold, semi-modular, 4 rails @ 18A each

Xigmatek Vector G 750w, 80 plus Gold, semi-modular, 2 rails @ 40A each

Antec HCG 750w, 80plus Bronze, non-modular, 4 rails @ 40A each

Silverstone Strider 750w, 80 plus Silver, full modular, 1 rail @ 62A

Say we want to power an 8350 and 2 crossfired 7950s. Which of these supplies fits the purpose? Or are all of them suitable?

As there is significant price difference between the first two and the later two, I would be inclined to use the FSP or Xigmatek. But with my limited understanding of PC power supplies would make me err on such a choice.

The Antec appears least preferential as it is non-modular, Bronze rated, and expensive.

If combined amperage is important, then the (relatively) low rated rails of the FSP beats the Silverstones single rail by 10 amps.

The FSP and Xigmatek are same price, but the FSP has a fan grill vs Xigmateks honeycomb opening. And from anecdotal evidence, grills make a less noticeable sound. I haven't noticed this myself, but I've seen it mentioned a few times on Tom's Hardware.

Finally, the OEM of each unit. Where can you find this information? From what I read:

Antec uses Seasonic units. FSP and Silverstone make many of their own units. I didn't find anything about Xigmatek PSUs. But this is all based on me trusting the word of some people commenting on, say, a PSU review by Anandtech or something similar.

And message boards almost always boil down to "just get a seasonic and be done with it". Well the similarly specced Seasonic unit is $60-$100 more expensive.

It just seems to me that the information out there on PSUs is either outdated, biased, questionable or confusing.

 

Maybe you friendly people can clear things up? Thanks for your time as always.

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The FSP would would be the last choice of mine; wtih multiple rails, you have to worry about plugging cabels into the right ones, so that you don't overload one rail by exceeding the power limits. If I were you, I'd get a Lepa G650, personally. You don't need 750W for 7950 CF, even OCed; you simply don't. The Lepa has 54 Amps on the 12V rail, and a single 12V rail. That is more than enough for 7950 CF, and most importantly, the unit itself has 4x PCIe 6+2 connectors, for 2-way CF. If you want to use a multi-rail PSU, which I don't advise below 1000W load, then make sure each rail has at least 40-50 Amps on the 12V rail; otherwise, you will easily overload them.

About the message boards talking about getting a Seasonic, that's because Seasonics are "typically" among the top in terms of ripple, efficiency, warranty, and build quality, but that does not mean they don't make shitty PSUs sometimes. Brands are really irrelevant most of the time; it boils down to OEM and warranty. Seasonic is their own OEM, so we can forget about specifics for now, but they also have a really nice warranty. So do plenty of other companies, though, especially units like the Corsair HX series, which has a 7 year warranty. To find the OEM, there are lots of good resources. Jonnyguru does some fantastic reviews, very thorough, and detailed, and they always include the OEM. However, a quick searh, for instance, "Lepa G650 OEM," will show you that, in this case, the OEM of the G650 is a CWT, which is a generally pretty nice OEM. Most Lepa units are rebranded Enermax PSUs, which are also their own OEM, becaues they have a huge partnership, but the lower-end units of any company are going to generally be a lower quality OEM.

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Plugging in the right cables. This is something I can't wrap my head around.

If I have a PSU with four rails. Say it has the 24 pin and 8 pin hardwired. But then it has 2 pcie 8pin and 2 pcie 6pin via modular. There is no choice in power distribution? One 8pin and 6pin goes in one GPU, the other 8pin and 6pin go into the other GPU? What mistake could you make if there is only one configuration?

That may sound dumb, as I have only used single rail PSU before, so I don't know.

I'm actually not in the market for a PSU just yet. I have an Antec Earthwatt 500w, and I can't justify an upgrade just for the sake of having more power. Oh, I only need to power a single 7950 right now. But maybe down the track a little bit..

I was actually thinking 650 would be enough for the crossfire. And the unit I like is Silverstone Strider Plus 650w, which has 49A on a single rail.

I've never heard of Lepa. Probably not available here. As usual.

 

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Where is "here"?

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Australia.