What would be a silent PSU that has 2 x 8 pin CPU plug?

PSUs: The source of DC power for all components in the PC & often a big noise source.

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Happy Hopping
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What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Happy Hopping » Tue Mar 19, 2013 1:48 am

http://resources.vr-zone.net/uploads/14 ... G_ws_1.jpg

I am buying this motherboard that need 2 x 8 pin CPU plug on top of the regular 20 pin

So far, I know that the Antec CP-1000 is silent and has 2 x 8 pin, but this item is discontinued.

Antec does have Quattro 1200 and HCP 1200 that support 2 x 8 pin, but I don't think they are silent.

So another fine choice should be the seasonic Platinum P 860, and if there is no other candidates, I'll go with this guy, as this little guy is 7 yr. warranty, but there is coil whine issue and very stiff cable reported w/ this model

Pappnaas
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Pappnaas » Tue Mar 19, 2013 2:47 am

Just wondering if you can't use some adaptors to get the second 8 pin working?

That would widen your choice of suitable modells.

flemeister
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by flemeister » Tue Mar 19, 2013 3:11 am

The Silverstone Strider Plus 750W has 2x 8-pin EPS connectors:

http://www.jonnyguru.com/modules.php?na ... y&reid=183

cordis
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by cordis » Tue Mar 19, 2013 11:27 pm

Interesting question. Here's a fun coincidence, I have that motherboard, and I'm currently on my 3rd power supply for the system. Whatever power supply you get, and this is very important, MAKE SURE IT HAS A SINGLE 12 VOLT POWER RAIL. One disclaimer, my system is fairly high powered, a dual E5-2687W that runs at 100% constantly with about 15 hard drives and a bunch of fans on top of that, so my power needs are somewhat high. Although my kill-a-watt said the max load to the wall was less than 600W. But here's what happened to me. My first PSU was an Antec Signature 850, but since that one has multiple 12v rails, I managed to char up one of 8 pin cpu plugs. Luckily my local repair place was able to fix the motherboard, but I learned my lesson, and moved on to a Seasonic SS-1000XP. That one lasted a while, but it failed about a month ago. Well, I haven't done a whole lot of testing with it in other systems, but it didn't work with the xeons anymore. I now have a Cooler Master Silent Pro Gold 1200W, maybe that will last longer. Seems stable so far, but I haven't reconnected the hard drives yet. See if it gets wonky or not.

But as far as your question goes, lots of the higher powered supply have dual 8 pin cpu plugs, but 1kW and above may be more than you need. On the bright side, the fans usually spin more slowly and quietly for high powered supplies with normal loads. Depending on your actual power needs, you might be able to get by with a smaller supply and an adapter, they do make them. Just make sue it has a single 12v supply line. Very important.

Happy Hopping
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Happy Hopping » Wed Mar 20, 2013 12:43 am

I have this 1 in mind after I done quite a bit of research

http://www.enermaxusa.com/psu_epm850ewt.php

How do I find out if it has 1 x single 12 V rail or not?

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by MikeC » Wed Mar 20, 2013 7:33 am

Happy Hopping wrote:I have this 1 in mind after I done quite a bit of research

http://www.enermaxusa.com/psu_epm850ewt.php

How do I find out if it has 1 x single 12 V rail or not?
It has 4 rails -- right on the specs tab of the page you linked.

The Seasonics all have single rails these days. Coil whine is one of those component-dependent issues that can hit any PSU. My sample of a 1000 Platinum Seasonic made no or little whine.
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by MikeC » Wed Mar 20, 2013 7:39 am

The Kingwin LZP-1000 is another contender. I found no whine/buzz on my test sample.
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by bonestonne » Thu Mar 21, 2013 11:25 am

I have an Antec HCG-750 and I use a dual molex to 8 pin adapter to serve the second EPS12v connector on my Asus Z9PA-D8 motherboard and it works fine.

So far, I haven't had any issues with any noise. The 3 hard drives in my system make more noise than anything else, but I would definitely have noticed any whining noises, and I haven't.
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Happy Hopping
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Happy Hopping » Thu Mar 21, 2013 10:26 pm

MikeC wrote:The Kingwin LZP-1000 is another contender. I found no whine/buzz on my test sample.

The Seasonics all have single rails these days. Coil whine is one of those component-dependent issues that can hit any PSU. My sample of a 1000 Platinum Seasonic made no or little whine.
Mike, thanks for your input. Why is it better to have 1 x 12V coil? They told me it's the other way around, that more than 1 x 12 V rail, is a better design. Are you saying there is some relationship on coil whine vs. more than 1 x 12 V rail?

No whine is better than little whine. As I suffer thru another computer for about 3 to 4 months of coil whine. It's a high end HP Z800 workstation, very surprisingly, after they replace the motherboard, the whine disappear. When it first happen on their 900W fancy non-cable style power supply, we swap about 2 PSU. The coil whine is non stop and unbearable. So I have to pull the power cord to stop the noise. In the end, HP finds out that the motherboard is causing the whine, in which I just can't believe. Regardless, w/ a newer REV of the motherboard, the problem goes away totally.

Since this subject come up, has any1 heard of this? In other words, has any1 experience coil whine, and the PSU is NOT the cause, rather, it's the motherboard?

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by MikeC » Thu Mar 21, 2013 11:29 pm

Happy Hopping wrote:
MikeC wrote:The Kingwin LZP-1000 is another contender. I found no whine/buzz on my test sample.

The Seasonics all have single rails these days. Coil whine is one of those component-dependent issues that can hit any PSU. My sample of a 1000 Platinum Seasonic made no or little whine.
Mike, thanks for your input. Why is it better to have 1 x 12V coil? They told me it's the other way around, that more than 1 x 12 V rail, is a better design. Are you saying there is some relationship on coil whine vs. more than 1 x 12 V rail?
One of the other posters in this thread talked about staying away from multi-rail PSUs for your board. I'm taking his comment at face value. In general, separate rails only do one thing: Limit the power deliverable on specific cables for safety's sake. All the 12V output cables are still wired in parallel, though; they are fed by one transformer/circuit. If the power limiters work as they are supposed to, you have to be careful about balancing the load on the output cables, because the original Intel requirement was to limit it to 240VA (or 20A on a 12V line). PITA and zero safety relevance in a computer. Which is why Intel eventually dropped this from their ATX12V PSU design guideline.
No whine is better than little whine. As I suffer thru another computer for about 3 to 4 months of coil whine. It's a high end HP Z800 workstation, very surprisingly, after they replace the motherboard, the whine disappear. When it first happen on their 900W fancy non-cable style power supply, we swap about 2 PSU. The coil whine is non stop and unbearable. So I have to pull the power cord to stop the noise. In the end, HP finds out that the motherboard is causing the whine, in which I just can't believe. Regardless, w/ a newer REV of the motherboard, the problem goes away totally.

Since this subject come up, has any1 heard of this? In other words, has any1 experience coil whine, and the PSU is NOT the cause, rather, it's the motherboard?
Yes, this is very common -- mobos can make the sound & they can cause PSUs to make it as well. Ditto video cards, especially the higher power ones.
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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by cordis » Sat Mar 23, 2013 9:10 pm

The reason you want a single 12V rail is that the cpus can potentially draw a lot of power, and in that case you'll have to make sure that the 12V rail you hook one of the cpus up to can support that power. The power draw is also much higher at start up, and the board won't even boot up if it can't get max power draw at start up. Or, you can wind up drawing too much power through one of the rails (like I did in my first set up) and it winds up driving higher current through the other connector to compensate, and you get a nice charred power connector. Now sure, you may not have that much power draw, but that depends on the cpus you want to use. Do you know what cpus you want to use with this board? That's a very important question to answer. But basically, getting a single rail supply should give you fewer headaches all around.

It doesn't have anything to do with coil whine. For the configurations I've used, coil whine hasn't been a problem with this motherboard. Of course, I'm trying to give the board a lot more power than it needs so start up issues aren't a problem, so YMMV.

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by lodestar » Sun Mar 24, 2013 3:55 am

IMO multiple rails with Over Current Protection (OCP) are probably a better idea. But the main point is that single rail or multiple rail should not really be an issue provided that the PSU has sufficient capacity. For this reason the 2X formula (maximum power draw x 2 = PSU watts) for sizing PSUs is probably more important - a PSU should not be loaded to the point where connectors start burning. Antec have published their take on these issues as part of the PSU myths series:

Myth 1: Only Single Rail Power Supplies Can Power Up High-end Graphics Cards!

Myth 2a: A Single-Rail Power Supply Is More Powerful Than A Multi Rail Power Supply!
Myth 2b: Multi Rail Power Supplies Lose Power Due To Their Separate Rails!


Myth 3: A Single Rail Power Supply Is As Safe As Multi Rail Power Supply!

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by cordis » Mon Mar 25, 2013 8:49 pm

Huh, it's funny that the psu that burned my connector was an Antec Signature. Hey, whatever, y'all can do what you like.

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Cistron » Tue Mar 26, 2013 6:08 am

cordis wrote:Huh, it's funny that the psu that burned my connector was an Antec Signature. Hey, whatever, y'all can do what you like.
You've got to weigh anecdotal vs. statistical evidence. Your unit might have been faulty.
wikipedia wrote:Multiple +12 V rails
As power supply capacity increased, the ATX power supply standard was amended (beginning with version 2.0[3]) to include:

3.2.4. Power Limit / Hazardous Energy Levels Under normal or overload conditions, no output shall continuously provide more than 240 VA under any conditions of load including output short circuit, per the requirement of UL 1950/​CSA 950/​EN 60950/​IEC 950.
—ATX12V Power Supply Design Guide, version 2.2[4]
This is a safety limit on the amount of power that may pass, in case of a fault, through any one wire. That much power can significantly overheat a wire, and would be more likely to melt the insulation and possibly start a fire. Each wire must be current-limited to no more than 20 A; typical supplies guarantee 18 A without triggering the current limit. Power supplies capable of delivering more than 18 A at 12 V connect wires in groups to two or more current sensors which will shut down the supply if excess current flows. Unlike a fuse or circuit breaker, these limits reset as soon as the overload is removed.

Ideally, there would be one current limit per wire, but that would be prohibitively expensive. Since the limit is far larger than the reasonable current draw through a single wire, manufacturers typically group several wires together and apply the current limit to the entire group. Obviously, if the group is limited to 240 VA, so is each wire in it. Typically, a power supply will guarantee at least 17 A at 12 V by having a current limit of 18.5 A, plus or minus 8%. Thus, it is guaranteed to supply at least 17 A, and guaranteed to cut off before 20 A.

These groups are the so-called "multiple power supply rails". They are not fully independent; they are all connected to a single high-current 12 V source inside the power supply, but have separate current limit circuitry. The current limit groups are documented so the user can avoid placing too many high-current loads in the same group. Originally, a power supply featuring "multiple +12 V rails" implied one able to deliver more than 20 A of +12 V power, and was seen as a good thing. However, people found the need to balance loads across many +12 V rails inconvenient. When the assignment of connectors to rails is done at manufacturing time it is not always possible to move a given load to a different rail.

Rather than add more current limit circuits, many manufacturers have chosen to ignore the requirement and increase the current limits above 20 A per rail, or provide "single-rail" power supplies that omit the current limit circuitry. (In some cases, in violation of their own advertising claims to include it. For one example of many, see [5]) The requirement was deleted from version 2.3 (March 2007) of the ATX12V power supply specifications.[6]

Because of the above standards, almost all high-power supplies claim to implement separate rails, however this claim is often false; many omit the necessary current-limit circuitry,[7] both for cost reasons and because it is an irritation to customers.[8] (The lack is sometimes advertised as a feature under names like "rail fusion" or "current sharing".)

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Re: What would be a silent PSU that has 2 x 8 pin CPU plug?

Post by Ranf1 » Fri Nov 22, 2013 3:36 pm

I've ordered this same motherboard, Asus Z9PA-D8, and am curious which PSU you ended up purchasing and your experience to date? Also, would appreciate which 2x4-pin to 8-pin molex adapter was used by the person with the Antec PSU as there's some risk to the motherboard/cpus in getting an incorrect part based on my research, but given the PSU model and adapter part# will minimize that risk! Thanks very much in advance.

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