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Just a few PSU questions

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#1 Sei


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Posted 29 April 2010 - 11:47 PM

So I hear a lot of things about the 12V rail being important. Can someone explain to me how this system works? My current PSU supposedly has 4 12V rails supplying up to 18A each. However, this PSU only has a single 12V rail supplying up to 70A and 840W.

Also, the powerbar I usually plug my PSU into has information on the back that notes Max Load: 15A 125VAC 60Hz

What does all this information mean and how does it affect my system? Does my powerbar limit my PSU to the Max Load it states and I should be going straight from the wall outlet instead? I'm trying to do a bit of research myself but I haven't found any real cohesive information to put everything together.

And of course, compatibility - would it work with this and this? Corsair's site says the PSU is SLI ready but what about Radeons and XFire? And what are the differences between the HX and TX series aside from the modular and non-modular setups respectively (quality, control, etc)?

Sorry for the hail of questions, but I hope someone will be able to help me clear things up!

Edited by Sei, 30 April 2010 - 12:16 AM.

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#2 dpunisher


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Posted 30 April 2010 - 09:09 AM

Background: http://en.wikipedia.org/wiki/Power_supply_rail

Multiple rails were designed to supply more power while maintaining the (then) ATX spec current limit of 20amps/12V (I think). Each rail would be current limited, and would switch the power supply off if the 20 amp/rail current was exceeded. Later on the specification was dropped from the ATX spec, but some manufacturers still adhere to it (Antec). Other OEMs like Seasonic trend toward single rail PSUs.

Having multiple 12V+ rails can sometimes be misleading as simply adding the 12V+ watts together often results in a bigger number than what the PSU can actually supply. Example, you might have a PSU with 3 12V+ rails rated at 20 amps/rail. You would assume the PSU would be good for 60 amps (720 watt) total 12V+, but if you look on the label it might say "50 amp maximum (600 watt) 12V+ combined".

As far as your powerbar, 15A X 125V= 1800 watts. Not a problem.

"SLI Ready" was/is an Nvidia marketing term. That PSU will work fine with Crossfire/SLI as it has all of the required connectors.

HX series are modular, meaning you use only the wires/connectors you need. TX are not modular. The newer HXs are a bit more efficient, but cost more. I think the TX units (except 950TX) are made on the CWT (Channel Well Technologies) PSH platform, the HX are a mix of Seasonic and CWT (the newer HXs are based on the CWT DSG platform). The new 950TX is a DSG. DSG are the new DC-DC units, higher efficiency, better voltage stability etc.

Edited by dpunisher, 30 April 2010 - 09:10 AM.

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