I am putting a new system together with all of the latest gizmo's. At least as far as I can afford, and it looks like I will need to pick a new Power Supply.

I'll be running Vista Home Basic x64 on a new MSI Motherboard with an AMD Phenom Quad Core 2.3 GHz, NVidia chipset, 2 600Gb SATA hard drives, 8 GB's of DDR2 800 MHz RAM, a 500 MB NVidia PCI-Express card, a Creative Audigy SE PCI sound card and an IDE DVD ROM and Burner.

I was hoping I could stick with my Coolmax 550 watter, but the Coolmax tech tells me otherwise, even though on the Thermaltake Power Supply Calculator it says I need only 525 watts. I'm not sure if I entered in all of the valiues correctly on that though.

So it looks like it's time to shop for a new Power Supply then, and right now I'm leaning on two of them, a very quiet Nexus 600 watter that I chose because I'm going with their case fans: 80 Plus Efficiency 600 Watt Silent PSU

And an Antec 650 watter:
SuperBiiz.com - Antec TruePower Trio 650 650W Power Supply
The Antec's a little cheaper because it's not as fancy, but reviews say it's very quiet. Plus I've always had good success with them.

So that's where I'm at right now. Down to those two, though open to other suggestions. Price is somewhat of a factor. I've spent quite a bit already on the whole system and I want to start slowing down the purchasing craziness, though I still do not want to stop short on as key an item as a power supply is.

One more thing. I was browsing New Egg for power supply's and I ran into this post from someone who appears to be looking at Power Supply's from an entirely diffrent angle than I am. I mean I'm tech savvy to a point, but I also know my limits. I was just wondering, first of all, if anybody can translate this to understandable English, and second, how right-on is this person?

Here's his post on power supply's:

"Don't just check total power output, find out what you need in the way of current on each power rail. If you need 20 A on your +12V rails and the supply only has 15A, it doesn't matter how many watts the supply puts out: don't buy it. Make certain that you have ENOUGH rails, too: sometimes, you need more than just two +12V rails for your setup."

"Don't just check total power output, find out what you need in the way of current on each power rail. If you need 20 A on your +12V rails and the supply only has 15A, it doesn't matter how many watts the supply puts out: don't buy it. Make certain that you have ENOUGH rails, too: sometimes, you need more than just two +12V rails for your setup."

I concur. Apply this logic to your choice of the two PS units.

Make certain that you have ENOUGH rails, too: sometimes, you need more than just two +12V rails for your setup."

That is not true! That is a marketing ploy to get users to buy bigger (read: more profitable) power supplies, under the guise of circuit isolation and protection.

With multiple rails, the power supply is forced to maintain some (significant) reserve current for each rail. This means if your graphics card has a sudden demand for 18A, your 30A supply has to leave 15A on each rail, so you are hosed, and the PSU shuts down the card. Not good. The plenty powerful PSU is not be able to deliver because it is forced to leave large (unused) chunks for the other rails. In order for a PSU have enough reserve on all rails at once to meet the needs of your computer, it has be bigger. On a single rail, all devices draw from a single pool. PC Power and Cooling is one of the more respected PSU makers - I recommend you read Power Supply Myths Exposed! Corsair is another major brand that follows the single rail concept.

That's not to say multi-rail systems are inferior, it just means you don't have to worry about individual rails, or pay for a bigger supply than you need. It also means the PSU's self protection circuits are less complicated with fewer parts. Always good. Note that some of the other (very fine) PSU makers, TT for one, incorporate added circuitry in their higher end PSUs that constantly monitor current demands and will instantly rob from rail 1 to feed rail 2 in short bursts. Sounds great. Sounds expensive, with little advantage to me. None of that "intelligence" is needed for 1 rail systems. However, if you are into serious, hard-core animated gaming or design, and have more than one monster graphics card, a multi-rail PSU may be the right, and only choice for you.

Use the eXtreme PSU Calculator Lite to determine your power supply unit (PSU) requirements. Plug in all the hardware you think you might have in 2 or 3 years (extra drives, bigger or 2nd video card, more RAM, etc.). Be sure to read and heed the notes at the bottom of the page. I recommend setting Capacitor Aging to 30%, and if you participate in distributive computing projects (e.g. BOINC or Folding@Home), I recommend setting TDP to 100%. Research your video card and pay particular attention to the power supply requirements for your card listed on your video card maker's website. If not listed, check a comparable card (same graphics engine and RAM) from a different maker. The key specifications, in order of importance are:

1. Current (amperage or amps) on the +12V rail,
2. Efficiency,
3. Total wattage.

Then look for power supply brands listed under the "Good" column of PC Mechanic's PSU Reference List. Ensure the supplied amperage on the +12V rails of your chosen PSU meets the requirements of your video card. Don't try to save a few dollars by getting a cheap supply. Digital electronics, including CPUs, RAM, and today's advanced graphics cards, need clean, stable power. A good, well chosen supply will provide years of service and upgrade wiggle room. I strongly recommend you pick a supply with an efficiency rating equal to, or greater than 80%. Look for the 80 Plus - EnergyStar Compliant label. And don't forget to budget for a good UPS with AVR (automatic voltage regulation).

From that link, under 8. ARE MULTIPLE 12-VOLT RAILS BETTER THAN A SINGLE 12-VOLT RAIL?
"PC Power and Cooling is once again leading the industry. All of our power supplies now feature a large, single 12-volt rail. The design is favored by major processor and graphics companies, complies with EPS12V specs (the 240VA limit is not a requirement) and is approved by all major safety agencies such as UL and TUV.3"

Sounds like a marketing ploy as well, by what, a power supply manufacturer!


Not wanting to debate, I "read around" things like this. Myths are myths are myths. All manufacturers are marketing their product. They'll use "myths" and a miriad of other ploys etc, as well as general advertising. They want you to buy it.

I look at what the specs say that component will deliver. If it meets my required specs (or better), I obtain the component.

The bottom line is, get the best power supply you can afford. As long as it's ISA (Industry Standard Architecture), it can be moved to any future ISA enclosure/system you may build.

No doubt their "myths" is a bit biased as well - nevertheless, it cost more to design and build more rails, as well as the circuitry to control multiple rails. And a single rail does not limit current to less than what is available. So my point was, assuming a quality maker and a properly sized PSU, there is no proven technical advantage, or need to using a multiple rail PSU over a single (except with two or more, power demanding graphics cards). Therefore, do not base and limit purchasing options on whether there are more than one 12V rail, or not.

And for the record, PC P&C is leading the industry in the push back to single rails. Whether all the rest follow or not, who knows. Some have, some are scaling back to fewer rails.

In either case, we agree to not go cheap on the power supply. Today's extremely high speed digital devices need good, clean, stable power, and they don't care where it is coming from.

No doubt their "myths" is a bit biased as well -

;>) As they all are. They're marketing their product. I select based upon performance and requirements and published specs.

(As an aside, in those "myths", they state that two PS fans won't move more air than one fan. Given the laws of physics, an x CM dia. fan, with x blades, at x pitch, at x RPM will move x CFM of air. If you place two of these in an enclosure (both mounted in exhaust mode), the x CFM has to be more than one fan. (Given that adequate ventilation openings are punched through the enclosure, while still preserving adequate electrical access hazard measures.))

And a single rail does not limit current to less than what is available. So my point was, assuming a quality maker and a properly sized PSU, there is no proven technical advantage, or need to using a multiple rail PSU over a single (except with two or more, power demanding graphics cards). Therefore, do not base and limit purchasing options on whether there are more than one 12V rail, or not.

I concur. Just select your requirements (especially if you have said graphics cards) amongst the (better/track proven) manufacturers and purchase.


My main point was;

Don't just check total power output, find out what you need in the way of current on each power rail. If you need 20 A on your +12V rails and the supply only has 15A, it doesn't matter how many watts the supply puts out: don't buy it.

I just included the entire statement as you'll find proponents to both views.

Given the laws of physics, an x CM dia. fan, with x blades, at x pitch, at x RPM will move x CFM of air. If you place two of these in an enclosure (both mounted in exhaust mode), the x CFM has to be more than one fan.

Since we don't know the givens - the point is moot. But I will note there are many single 120mm fans that move more air than two 80mm fans. I would rather have a single 120mm, they are quieter.

Since we don't know the givens - the point is moot.

I don't see how, however, we're not here for a fan topic.

Just;

... get the best power supply you can afford. As long as it's ISA (Industry Standard Architecture), it can be moved to any future ISA enclosure/system you may build.

I don't see how...

Well (since the OP has not returned) because as you noted, there are many factors that determine the amount of air flow that can be moved through a set space, besides the number of fans. We don't know the characteristics of the fan or fans in use here. It could be a monster 140mm fan, such as the Corsair TX750. I have one of these and it pushes some air out the back, but I have to get up on it to hear it - a very good thing, IMO.

OK, forget all the other givens, fan brands etc. Consider only CFM. Take any two identical fans. These fans will move lets say 1.2 CFM of air each.

With two of these mounted in a given enclosure (both mounted in exhaust mode), and, the enclosure has adequate (intake) ventilation holes/slots/orifaces/etc punched in it to enable 2.4 CFM of air flow, then that's what you will get. 2.4 CFM of air moving through that enclosure.