nForce2 Power Supply (PSU) FAQ

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Power Supplies
What is the one most commonly overlooked component in a computer? The power supply! Many people rely on the cheap power supplies that come with their computer case, not realizing what risks and potential problems it can cause. This worked on old machines, but today's technology isn't quite as forgiving.

Machines need "cleaner" power-power without a lot of voltage fluctuations. Voltage fluctuations can cause stability problems, and can potentially (if they are drastic enough) damage your motherboard and computer components.

Plus another concern is under-powering your equipment. This leads to hard drive malfunctions, boot problems (fans and hard disk spinning but no video), stability issues, and can also potentially kill your valuable computer parts.

With all the features crammed into most nForce2 boards, a bare minimum Power Supply would be one that can supply 20-24amps on the 12v rail. This generally means a PSU that is at LEAST 350 watts. This is important, as the 12v rail powers your CPU, your motherboards onboard components, your hard drives and fans. As well you will want to make sure you have plenty of amperage on the 5v rail, as most of the video cards with extra power plugs on them use it, and some motherboard components rely on this rail.

A good and reliable brand-named PSU can save you a lot of grief and reduces the chances of it frying and taking your prized rig with it. It also comes with a warranty, which is more than can be said with many of the generic power supplies you will find coming with a case. Many of the generic power supplies on the market may say that they are 350w or 400w or even 500w, but in reality they can't support that much current at a time. The kicker is that nForce 2-based mobos use a LOT of current, and will either not function without enough power, or it will cause the PSU to fail, with the potential to seriously damage itself in the process if the PSU doesn't have proper safety mechanisms (which most cheap ones do not).

So if you don't have a good one and think you are having problems with your PSU, or you simply want to have a little assurance that you do have enough power. It might be time to invest in a new one. The two most common reliable brands are Enermax and Antec. But keep in mind how much power you need, and make sure that the 12v and 5v rail can support your rig. Avoid generic cheapie PSUs, they will certainly cause problems. Enermax PSUs have awesome amps on the 12v rail (a 350w Enermax delivers 26a on the 12v rail, which is 2 more amps than an Antec True Power 550w). However Antec TruePower branded PSUs offer "cleaner" power with less voltage fluctuations (ATX 2.03 standard dictates a fluctuation tolerance of ± 5% on the 12v, 5v, and 3.3v rails; Antec TruePower offer a fluctuation tolerance of ± 3%). There are also several other brands available that do offer quality products, so keep your eyes peeled, and watch those rails

Board Features Relating to the Power Supply
GIGABYTE Dual Power System
For those with the Dual Power System (DPS, DPS K8 and DPS Gold ) daughter-card (GA-7NNXP, GA-7NNXPV, GA-K8NNXP, GA-K8NNXP-940, GA-K8NSNXP and GA-K8NSNXP-939) that provides an additional 3-phase voltage regulators to bring the total up to 6.

What is a "3 Phase" or "6 Phase" voltage regulator? It has to do with the number of pairs of MOSFETs involved in the power filter ("cleaning") system. The more phases involved, the "cleaner" the power provided to the motherboard is. This means less voltage spikes, and less stress on components which means more stability.

The 7NNXP and 7N400 Pro (original) boards have 3 pairs of MOSFETs (little black boxes w/ 2 connectors out of them to the board's PCB), for every two MOSFETs there is one coil (it's a small cylinder of metal with copper wire wrapped around it). These make up the 3-Phase power filter system. Each DPS has an additional 3 coils and 6 MOSFETs. So, with the DPS installed, you now have a 6-phase power filter system. This theoretically should bring greater stability and life to the motherboard and components.

It should be noted that there have been many reports of problems with the DPS with lower amperage power supplies that have been fixed with a better PSU, while others have been able to have the DPS work with lower amps. Then there are others who can't get it to work no matter what. This all seems to be depending on luck more than anything, as the DPS itself can cause problems.

ATX 12v Connector
If your board has an additional ATX 12v power connector (it's a square divided into quarters) you MUST use it. If your PSU does not have this connector, you should stop using it, and replace it with a PSU that does have one ASAP. This connector is very important for regular operation of your motherboard, as it reduces stress on the main ATX connector and prevents the main connector from failing or malfunctioning. If you do not use it you will sooner or later have a potentially dangerous to both you and your rig malfunction.

All links compiled by DaFanMan!

Must Read:
http://www.firingsquad.com/guides/power_supply/page4.asp
http://compreviews.about.com/cs/casesandmods/bb/aabybpsus.htm

Truths and Misconceptions:
http://www.extremeoverclocking.com/articles/guides/Power_Supply_Guide_2.html

How a PSU works:
http://computer.howstuffworks.com/power-supply.htm
http://compreviews.about.com/library/weekly/aa-psus.htm
http://www.thetechboard.com/tutorials/atx.php

Linking PSUs Together:
http://www.procooling.com/articles/html/linking_multiple_psu_s_as_one_.php
http://www.picard.demon.co.uk/atx.htm

PSU Reviews:
http://www.tomshardware.com/howto/20030609/
http://www.tomshardware.com/howto/20021021/
http://www.amdboard.com/psu.html

Listing of brands of PSU and their amperages:
http://pages.sbcglobal.net/adunlap/psudatasheet.html

Specifications:
Warning: This info needs Adobe Acrobat Reader to view-http://www.formfactors.org/developer%5Cspecs%5CATX12V_1_3dg.pdf
http://www.compute-aid.com/atxspec.html

Another PSU FAQ:
http://www.duxcw.com/faq/ps/ps4.htm

[Disclaimer] If you're currently using a cheap PSU and everything works, that's great! However, that doesn't guarantee that the same cheap PSU will work for someone else, or that their cheap PSU will give the same results as your experience. The reason behind recommending quality PSUs is two-fold: It makes it easier for others to help users as they can then remove the PSU from the troubleshooting equation, as well as ensuring that the user is not potentially under-powering his or her rig.

This makes the troubleshooting list a bit shorter, and helps to cut down on the time needed to help someone get their prized rig back up and running.
[/Disclaimer]

[Lord-Elendil]

Stitch that 12v atx connector should always be connect no matter what PSU you have...I read the manual a lot when I had my problems and it clearly states in the 7NNXP's manual that failing to connect the 12v atx connector may keep the system from booting up. As always its better to be safe then sorry, besides, where else are you going to hook up that thing?

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Lord-Elendil, I was actually trying to get that point across, no matter what I'll edit it and make it look more forceful

[Lord-Elendil]

heh ok forceful is good

[Viridescent]

I bought a an Enermax 550watt power supply over christmas Now everything in my system runs better! My cpu is now at 45 degrees celsius at idle and 50 at load. It use to be running at 70 to 77 degrees. I thought it was the crappy heatsink. Nope. This is proof of what a good power supply can do for a system.

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Also the fact that better quality PSUs (exempting TurboLink PSUs ) have two fans to aid in cooling, that is part of the specifications for AMD and Intel rigs helps with temps too

[DaFanMan]

Very good job stitch
That's got good flow to it, gets the point across very nicely.
Im still seeing power related issues everyday, unfortunately the efforts to educate are usually mis directed by those who persist in telling users that there 250-300 watt psu is more than adequate and that their problems must lie elsewhere.

Im thinking down the line, many that refuse to acknowledge the basics today are really gonna be suprised when they move up to The A-64 platform systems featuring a gig of ram minimum and all of the other trimmings at what the power requirements for a rock solid stable system will be then.

Again,
good job putting all of that info together, it should be of great benefit to many of the users that pass thru here.

Laterz,
dafanman

[DaFanMan]

bump

[Xyrium]

Also the fact that better quality PSUs (exempting TurboLink PSUs ) have two fans to aid in cooling, that is part of the specifications for AMD and Intel rigs helps with temps too

I always wondered what type of vacuum effect the interior PS fan causes when you have a rear case fan trying to pull air out just below it. The two are fighting each other to exhaust air. Oh well.

I just droppd in a Gigabyte N400Pro2 and the CPU (Athlon 2GHz) is currently running at 50C. Guess I'll have to wait a few days for the thermal grease to settle in. See my post on the new board in a few minutes. Nice PS post though stitch!

Rgds,
Paul

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Thanks everyone for the compliments