Some questions about the Corsair HX620W

[granulf]

I'm going to buy the Corsair HX620W :) . A few questions though:

 

1) I heard rumors that the PSU only has one large 12V rail instead of 3. Is that correct? I'm a fan of one big rather than 3 rails. Does that mean that I in theory could draw 600w from just one cable from the 12V rail, instead of the normal 18A shut down feature?

 

2) Noise. I saw some posts regarding ticking sounds etc. Is this a normal problem with these PSUs? I want it quiet :)

 

3) Would I be able to run 8800gtx sli and still overclock the GPUs and the CPU? I don't really plan running SLI, but you never know :D

 

 

Thanks.

[Iron Chef]

The HX620W has 3 Rails. each able to offload to another rail in case of overload, as well as able to pull from another rail if underload.

 

The HX620W is officially certified up to, and including Dual GeForce 7900 GTX or Dual GeForce 7800 GTX 512 MB. But the Corsair guys themselves have stated many times they have run all the way up to 8800GTX in SLI on the HX620W

 

The noise is not common, it only seems like it on this board because people come here if they have a problem, what you dont see are the hundreds of thousands+ that have perfectly working PSU's (like me!)

 

I'm new here though, so this info may not be 100% accurate.

[granulf]

Ok, because I read this review at jonnyguru.com: http://www.jonnyguru.com/review_details.php?id=32&page_num=2

 

Looking at the Seasonic main PCB inside the Corsair PSU reveals only two rails, labeled 12V1 and 12V2. There is no third rail. This is illustrated well at Hardware Secrets. Although I can not say that these rails are or are not somehow electronically separated in the PSU's circuitry somewhere, I did find that there was no OCP (over current protection or "limiter") on either of these rails as I was able to load any given connector up 30 to 40A with no drop in voltage, system shut down, etc.

 

So it is my opinion that we essentially have a single 12V rail PSU here.

 

The way I understand this, is that you could draw all 12V power from one connector? He clearly states that he tested a load of 40A from just one connector, which must mean that there is only one rail? :confused:

[jonnyguru]

Ok, because I read this review at jonnyguru.com: http://www.jonnyguru.com/review_details.php?id=32&page_num=2

 

 

 

The way I understand this, is that you could draw all 12V power from one connector? He clearly states that he tested a load of 40A from just one connector, which must mean that there is only one rail? :confused:

 

Lemme ask you this... What difference does it make? ;)

 

The only disadvantage to having the single 12V rail is that you don't have the inherent "overload protection" that would prevent more than 20A from going down one connector (which could potentially exceed the spec of the wire and connector)

 

Fortunately, that scenario is impossible since no one, two or three components could or would draw that much power. Unless of course you added a bunch of Y-Splitters and PCI-e adapters to a single Molex connector. ;)

 

If there's a short to ground, like a bare wire or fried component, which could put a load exceeding recommended specs on a single connector, then the PSU's short circuit protection kicks in and the PSU shut off before things catch fire.

 

Multi 12V rails does have a small advantage of somewhat isolating RF from one device to another, but the actual effectiveness of this is minimal.

 

The NICE thing about a single 12V rail is that any power is available to any connector at any time. I think I'll take that advantage over any of the "dis-advantages."

 

Here's a really good read about the myths and realities of single vs. split rails:

 

http://xbitlabs.com/articles/other/display/atx-psu5.html

[granulf]

Thanks for replying. I don't think you got my point, i do really want to have one single 12V rail! The reason for that is that in the future load may exceed 18A on one of the rails, thus causing it to shut down. But with one big 12V rail I won't have that problem, right? :o:

 

Just to be absolutely clear about this, The Corsair HX620W does have one single 12V rail, thus allowing me to use more than 18/20A from the 12V rail?

 

Just put my order in on it now, hope I will be happy :cool:

[jonnyguru]

LOL...

 

Ok. I just didn't want to contradict what Corsair is telling you.

 

The OEM for the Corsair unit intentionally removed the OCP circuitry that makes their PSU's multi-12V rail. So the answer is, yes. The Corsair is a single 12V rail PSU. It's built like a multi-12V rail because by design, that's what it's supposed to be. But none of the circuitry is there to make it multiple 12V rails. It has one 12V source and nothing preventing as much amperage as necessary from going to where it needs to go. :D

[granulf]

LOL...

 

Ok. I just didn't want to contradict what Corsair is telling you.

 

The OEM for the Corsair unit intentionally removed the OCP circuitry that makes their PSU's multi-12V rail. So the answer is, yes. The Corsair is a single 12V rail PSU. It's built like a multi-12V rail because by design, that's what it's supposed to be. But none of the circuitry is there to make it multiple 12V rails. It has one 12V source and nothing preventing as much amperage as necessary from going to where it needs to go. :D

 

Ok, great, it's ordered now and can't wait to get it :D

[Lord Chaos]

Let me chime in and say that I have the 620W and with topmodern equipment (check specs by name), and it runs flawlessly and makes almost no noise on its own.

[RAM GUY]

And the HX520W and HX620W both will share the load to a point and can exceed more than 18 amps per rail. We have ran both PSU's in Quad SLI configuratiosn with out problems so I dont think you will have any problems.