The Power Supply Thread

[jonnyGURU]

Disclaimer: A lot of this material is from jonnyguru.com or PSUInquisitor.com or may end up on either jonnyguru.com or PSUInquisitor.com. If credit is due elsewhere, I will note it. I'm just posting it here because there's no power supply forum at Anandtech and it seems that the same questions get asked over and over again, and in some cases incorrect answers. Maybe this will get stickied. Maybe it'll just end up as someone's search result. Either way, I hope the information helps...

The power supply is the single most overlooked component in a computer system.

CPU's, RAM, video cards, hard drives... at a performance level, any of these components can easily cost hundreds of dollars each. Yet the one component that powers everything in your machine, and could potentially screw up everything in your machine, is still the one component most people hesitate to spend at least $100 on (there are VERY FEW acceptable exception.)

(Paragraph from Directron.com) A PC power supply is one of the most important components in a computer, yet it is often the least appreciated due to its "low-tech nature". When a power supply is dead, your entire system is dead. A bad computer power supply could also cause other parts of your system to fail. As personal computers become ever more powerful, the importance of a reliable power supply is more than ever before.

A power supply that has fluctuating rails can cause lock ups, crashes, etc. The ATX standard has quite a bit of tolerance; 5%. Regulators on the motherboard and other components have even more tolerance. But when a power supply has weak rails, voltages can easily drop below these tolerances. Sometimes a multimeter can't even pick up these sags in voltage because they happen so fast. But all it takes is a sudden dip to lock up your system.

MOST power supplies have protection that prevents overvoltages, undervoltages, short circuits and high temperatures from killing other components. But just like any other component in your PC, failures are unpredictable and these protection circuits can fail. When this happens, damage can occur to components.

 

[jonnyGURU]

Picking the right power supply

Quality:

Common sense is going to tell you that the best way to determine the quality of a power supply is to stick with a brand that?s known for quality products. Also, COMPETENT reviews help as well.

One indicator I?ve used is the UL number of a power supply. UL actually certifies that a product is "safe" to use within a determined operating range and environment. Although I don't believe they actually load test every power supply, cross referencing a UL number can be handy for many reasons.

You can use a UL number to find out who actually makes a particular power supply. Also, if the UL logo is on the same label as the specs, you can be pretty sure that the UL listing pertains to the specs on that very label. Can you believe that there are a few companies that claim UL listing, but don?t put the logo on their label? That?s because the specs on that label are not the specs given to UL. And it?s a regular Easter egg hunt trying to figure out what the actual specs are using the UL number. So why bother? If the company can?t put a UL logo on the same label as the specs, they have something to hide and not worth doing business with.

Another way to classify the quality of a power supply is just from its weight. Simply put, a good power supply has good components in it. A better power supply has larger caps, transformers, heatsinks and overall more components than a cheaper unit. All of this adds up to more weight.

Also keep in mind the ?get what you pay for? adage. It doesn?t always apply from brand to brand, especially if people take into consideration USEFUL improvements like modular cables, active PFC, etc. all add to the cost of a power supply. But when you see a power supply with a bunch of lights and other pretty things, you have to take into consideration that this added bling isn?t free.

 

[jonnyGURU]

Picking the right power supply

Watts don?t mean squat!! Know how to read the label!

All a wattage rating is on the box of a power supply is the total capability of ALL of a power supply's rails COMBINED. The 5V, 12V, 3.3V, -12V, -5V and 5VSB capability are all added up to calculate a power supply?s ?wattage rating.? That total number really tells you nothing about the power supply's actual capability.

First you have to ask, is that wattage continuous power or maximum peak power? Some power supplies will give you output ratings based on what the power supply can continuously output, while others give you peak power. For you audiophiles, this is similar to the difference between RMS and Peak. Some companies will actually rate a power supply at what it can continuously put out, but with a tolerance of 10% +/- from actual spec! Intel?s ATX spec only allows for a 5% tolerance!

There's also variables that come into play like ?what was the temperature at which the testing was performed?? ?For what period of time was the testing performed at the specified wattage?? Basically, you should look at the amperage each rail is capable of and then just consider that the power supply's BEST CASE SCENARIO capability.
The first thing you can do is to try to figure out your computer's WORST CASE SCENARIO load. There are several calculators on-line that allow you to "add up" your computer's power. Unfortunately, the bulk of these give you a final calculation in wattage. Later on, I?ll give you a little formula I use to calculate how much power I think I need on the 12V rail (the most important rail in a modern PC.) 3.3V and 5V just follow.

You?ll soon enough figure out how important the way the manufacturer distributes power across the rails really is. If you have a 500W power supply with 40A available on the 5V line and you're using a Prescott with SLI video cards, you might be in trouble because the 5V line alone is using up 200W of that power supply's total power not leaving much else for other rails! Given that most power supplies give you 20 to 30A on the 3.3V (which is way high by today's standards, but even 30A on the 3.3V is only 100W) and split up about 20W for negative voltage and stand by, you're only left with 180W for the 12V rail. That's only 15A! Mind you, we're talking maximum combined peak power, but better safe than sorry, right?

If you don't have the time or resources to do this, then just do this instead: Try to figure out if your PC is going to be 5V heavy or 12V heavy, and then buy the biggest, best quality power supply you can afford with the load balanced most appropriately for your PC. For example: If you have a Pentium III or an Athlon XP board without an ATX12V connector (like Biostar Socket A motherboards never have the 2x2 connector) then something with a relatively high 5V is most suitable for you. If you have a Prescott or an AMD64, consider something with a high 12V rail or rails (combined wattage) like a Silverstone ST56ZF or an OCZ 520ADJSLI. If you have PCI Express video card or cards, consider something with a really, really high 12V rail or rails (combined wattage,) like one of the SLi approved power supplies on nVidia's website.

So now back to helping you guys and gals read a PSU label. Use this as a reference: http://www.jonnyguru.com/PSU/NexthermPSU460/P1010227.jpg

This one is very simple. This power supply gives us 30A on the +3.3V rail and 30A on the +5V rail. Underneath these two, you?ll see where the maximum combined capability of these two rails is 150W. That means, you can load up the +3.3V to 30A by itself, and you can load the +5V rail up to 30A by itself, but you can?t load them both up to their maximum simultaneously. The rails are not additive. You?ll also see 0.5A on the ?12V and 2A on the +5VSB. I?ll get back to the 12V rails in a minute.

Note that the total power of this particular power supply is 460W.

Ok? Now look at the 12V rails. There?s two 12V rails (I?ll explain why later) and they are rated at 18A each. The maximum combined wattage of those two rails is 32A.

What?!? But 18A plus 18A is 36A? Like the +3.3V and +5V rails I just mentioned, +12V rails are not additive. You can load each one up to 18A, but you can?t load them both up to 18A.

Now let?s go back to the ?watts don?t mean squat? phrase. I don?t want to slam any brands, but take a look around at some 500W and 600W units. You?ll actually find that even though they may have more ?total wattage? than this particular unit, this unit actually has more USABLE power on the 12V rails. Pretty interesting, right?

 

[jonnyGURU]

Picking the right power supply

So why do they split up 12V rails?

With the demand on +12V becoming greater and greater, Intel decided it would be "safer" to split the duty of supplying +12V across two rails. It's "safer" because inexpensive transistors capable of supplying more amperage (say more than 34A) at any kind of decent efficiency (70% or better) are subject to blowing up. I guess that's not very ?safe.? ;-)

To split the duty up between two (or more) +12V rails, one can use cooler running, cheaper transistors to supply the power. Furthermore, this isolates devices on one rail from another, so EMI introduced by lighting inverters and drive motors can be isolated from sensitive components like the CPU and video card.

Some people have questioned the principle of multiple 12V rails.

And for good reason! But I don?t think multiple 12V rails in general should be shunned. But it?s best to know what rails go where when considering using a multi-12V rail power supply with a high end system.

ATX specifications only say that the CPU (the 2x2 4-pin connector) is put on a separate rail from the ATX connector (the 20 or 24-pin) and the drive (also used for fans, lights, etc.) power connectors. They also specify that no one rail should have more than 20A available on it (that?s their ?safe? limit, so to speak.)

So if you breeze through reading that, you would say ?Ok. The CPU gets it?s power from the 12V2 and everything else gets it?s power from the 12V1.? But then you realize there?s a problem with that. 20A for just a CPU, even a dual core or even a dual CPU, is overkill. And 20A may be enough for some drives, lights, fans, etc. But what about PCI express video cards that regulate their voltage from the 12V rail via an auxiliary 6-pin connector? High-end video cards can easily tax 7A or more EACH off of the 12V rail. 20A leaves zero overhead.

Unfortunately, some power supplies adhere to the ?quick read? version of the ATX standard and put everything but the CPU on one rail. This is where everyone seems to be running into problems. Fortunately, some other power supply companies have gotten creative with rail distribution. I?ve seen power supplies with the PCI express connectors on 12V2 and even some with one PCI-e connector on each of the two 12V rails. THESE are the kind of dual rail power supplies you need to look for.

Some power supplies have more than two rails. The Antec NeoHE, for example, has three. Two modular connectors are labeled for 12V3 use. These are the two ports one should plug their PCI-e connectors into. Other power supplies have four 12V rails. These typically adhere to a standard other than ATX called ?SSI? but PCI-e is taken into consideration by keeping the PCI-e off of the same rail as all of the drives. Even if a PCI-e is plugged in using a typical drive Molex, that rail is still separate from the ATX connector, and the 2x2 4-pin connector.

 

[jonnyGURU]

Picking the right power supply

Calculating how much juice you need on the 12V rail:

First; do you have a Socket A CPU? If so, does it have a 2x2 12V connector? If not, you can stop reading after a few as the bulk of this text simply does not pertain to you. Your CPU?s core voltage is regulated off of the power supply's 5V rail and you?re putting as much as a 15A load on the 5V rail just for your CPU. This means you should rule out a few things when looking for a power supply:

Socket A board without a 2x2 12V connector:

• Do not use a dual 12V rail power supply. One of the two rails on a dual 12V rail power supply is for the 2x2 connector, so your power supply will have a rail you're not even capable of using!

• Do not get a power supply with a higher amperage on the 12V rail than on the 5V rail. I know future-proofing is a usually a good thing to do, but typically when a power supply with a high 12V capability is hit with a heavy 5V load, even when it's within spec, there's a thing called "crossloading" that happens. Essentially, your 5V dips below tolerance and your 12V shoots above. Side effects include lock up or even system shut downs due to over or under volt protection!

Now for the rest of you... You have a 2x2 12V connector on your motherboard, which means your CPU regulates it's core voltage from your power supply's 12V rail.

This is where I prove to you why you shouldn't go by the wattage of a power supply...

Let's start with a base system of an Athlon XP 3200+ and a high end AGP video card without an auxillary power connector (like an nVidia 6600.) Even if all you have is a single hard drive and a single optical drive.

• You're going to need a power supply with at least 17A on the 12V rail.

This number is pretty low because AGP cards get a lot of it's juice from the 3.3V rail via the AGP slot. But the AGP slot is only capable of supplying so much voltage. So what if you want a more powerful video card?

Let's say you have an AGP video card with an auxillary power connector (like a 6800.) The power connector supplies up to an additional 6.25A of 12V to the video card. So now we should look for a power supply that has more juice on the 12V than our initial build.

• You're going to need a power supply with at least 24A on the 12V rail.

Adds up quick, doesn't it?

Now let's say you have a Pentium 4 and an AGP card instead of an Athlon XP. Or that you have more drives, PCI cards and some fans other than the CPU fan.

• Add 2.8A to the 12V rail for Pentium 4 processors. Add 3.4A to the 12V rail if the Pentium 4 is a Prescott.

• Add 1.5A to the 12V rail for each additional hard drive.

• Add 1.5A to the 12V rail for each additional optical drive.

• Add .5A for each fan in your system.

• Add .5A for each PCI card in your system.

Now let's do some builds with PCI express video cards.

Since Socket A chipsets don't support PCI express video cards, we're going to switch the CPU in our base build to an Athlon64. That has a 7.4A requirement on the 12V rail instead of the 6.4A of the Socket A CPU. The PCI express slot can handle more juice and the PCI express card gets most of it's juice from the 12V rail. So our numbers change a little bit.

• 18A is enough juice on the 12V rail if you have a single PCI express video card without an additional power connector.

• 24A is enough juice on the 12V rail if you have a single PCI express video card with a connector for additional power.

• Add 1.75A if your Athlon64 CPU is an X2 model.

• Add 1.8A to the 12V rail for Pentium 4 processors. Add 2.4A to the 12V rail if the Pentium 4 is a Prescott.

• Add 3.4A if your Intel CPU is a dual core Pentium D

• Add 1.5A to the 12V rail for each additional hard drive.

• Add 1.5A to the 12V rail for each additional optical drive.

• Add .5A for each fan (other than the CPU fan) in your system.

• Add .5A for each PCI card in your system.

Now we get into dual PCI express video cards. Let's say you're using SLI or ATI's Crossfire. One would think that two video card means twice the power requirement, but that's actually not true for the same reason as your performance not doubling when you have two video cards. The additional power requirement for the second video card is still fairly significant, though.

• Add 4A if you have a pair of video cards and neither of them have their own power connector.

• Add 6A if you have a pair of video cards with a power connector for each.

Now keep in mind that these numbers are VERY liberal. All of the numbers are PEAK and in the case of different clock speed CPU's or GPU's within the same "family," I just used the highest number possible. This is because I can't possibly address every possible scenario of thermaldynamics and chassis layout that each and every one of you guys may have. I'd rather judge on the side of caution and just suggest that you have "more" power available, rather than "just enough." Truth be told, you might be able to get by with as little as 75% of what you may have calculated. But that might only apply to you and not everyone else here. Just keep in mind that more than anything else, this post should convey to you the importance of the 12V rail in a modern system and prevent you from buying one of these "480W" power supplies with only 18A on the 12V rail!

You may find that if you have a Prescott and a pair of 6800's with four hard drives, two optical drives and three fans that you may need 490.8W on the 12V alone (40.9A!) Such a power supply may be difficult to find, so keep in mind that's going to be a worst case scenario power requirement. All of the numbers listed are an average (since different brand drives, etc. have different power requirements) of the peak power requirements for each device. So to add all of the numbers up, you would theoretically be looking at the power requirement for your entire PC if every single component was running at maximum capability. That's CPU at 100%, all hard drive spinning, all optical drives spinning, all fans blowing and both video cards pushing as much FPS as they're capable of. Likely? No. So here's what we want to do now:

• Feel free to take your total number and multiply by 95% if you had to add to the 18A and 24A base numbers for your CPU (but NOT if you only had to add to the base because you have two video cards.)

• Multiply your number by 90% if you had to add on due to additional drives, fans, PCI cards, etc.

This will account for the unlikelyhood that everything in your machine will be running at full capability. For example, if we had an Athlon64 with a pair of 6800's, we'd still want to look for something with at least 30A on the 12V rail. But if we had a Prescott, we don't need to make that power supply one with 34A on the 12V rail. 30A should still do fine.

And if we added a second hard drive, optical drive and a couple fans to our build, we don't need 38A. 32A should do the trick.

 

[jonnyGURU]

Picking the right power supply

Efficiency:

The calculation for efficiency is DC Output divided by AC Input.

When a power supply is more efficient, it will use less power from the wall than one that is less efficient even if it produces the same amount of DC power.

The obvious upshot of this is a lower power bill. But also, the difference in wattage is dissipated in heat. So a more efficient power supply runs cooler. This can be used to an advantage one of two ways. One: A power supply will last longer if it?s not exposed to prolonged temperatures. Two: A quiet fan can be installed because not as much air flow is required to cool a more efficient power supply.

Efficiency ratings are very subjective, though. First off, no power supply is going to have the same percentage of efficieny all across the board. One may be 75% efficient at 200W, but drop down to 70% under a 300W load. Some power supply companies only tell you what the best efficiency is, but not at what load that power supply obtains that efficiency. Other power supply companies only tell you worst-case scenario, like "70% nominal at full load." Some power supply companies may be rating their efficiency at 230V instead of 115V. A PSU that runs at 230V is often more efficient because higher voltage means lower amperage and lower amperage means less resistance and less resistance means less heat. Q.E.D. Furthermore, a power supply may be more efficient at a lower ambient operating temperature than another. If a power supply is 80% efficient at 20C, that doesn't mean it's 80% efficient at 50C. This will lead me to explaining "de-rating curves" in my next post.

 

[NaOH]

Good read. ::thumbsup:: Very in depth.

 

[jonnyGURU]

Picking the right power supply

De-rating Curves:

A de-rating curve is something every power supply is subject to. As a power supply gets hotter, it?s ability to output power is reduced. This relationship is called a de-rating curve.

For example; most decent power supplies are rated at 20C and have a de-rating curve of 2W per degree C. That means for every degree over 20C, your maximum sustained output is reduced by 2W. So in a more typical ambient temperature of 50C, a 500W power supply may only be able to output 440W. It?s not a substantial loss of power, but not all power supplies have this de-rating curve and not all environments are at or below 50C and typically even a power supply with a good de-rating curve can drop exponentially when temperatures exceed 50C.

So how can you ?tame the curve?? There?s lots of ways. One is to simply buy a lot bigger power supply then you actually need. That?s a no-brainer. The other thing you can do is make sure that your power supply is not solely responsible for evacuating heat out of your chassis. Make sure you have a fan in the back below the power supply to exhaust heat, but also make sure you have an intake fan for positive pressure, because it the pressure inside the chassis is less than the pressure inside the power supply, you can actually DEFEAT the airflow of the power supply! I?ve seen a few instances where a user had a 120MM in the back and no intake. The PSU was trying to also suck air into it?s housing, but the vacuum caused by the rear exhaust fan actually reversed the airflow going through the power supply! Very not good.

UPDATE: In PC Power and Cooling's "Power Supply Myths exposed" they show a "500W" with a de-rating curve of 4W/1C. This isn't completely fictitious, but I don't think any of you guys are using the kinds of power supplies that have a 4W/1C de-rating curve.

 

[jonnyGURU]

Picking the right power supply

Resistance: Modular connectors, adapters and splitters.

Years ago, there was this cat named Ohm and he explained to us that resistance sucks.

Ohm?s law as it pertains to resistance in electrical current is R (resistance) X I (current) = V (voltage.) So you can see, the greater the resistance, caused by either length of wire, gage of wire or having to go through connectors and/or the greater the current, the less voltage you get.

In simple terms, having a modular power supply may drop your voltage a little because of the resistance between the modular interface and the cable. And using a 20-to-24 pin adapter or any kind of splitter can cause a slight drop in voltage because of the resistance caused by any imperfect contact between the pins of such an adapter or splitter. But on that same note, every single connection you make (PSU to drive, or motherboard, or video card) is another connector that is going to create a little more resistance.

There?s been a lot of scare tactics used to convince people to not go with a modular power supply. But the reality is, even at high loads the resistance is quite minimal if the correct measures are taken. For example: A PCI-e cable is going to have less resistance if there?s 3 12V leads on each side of the cable and 3 grounds on each side of the cable. Unfortunately, some modular power supplies may only have one or two wires split into three for each row for a PCI-e connector. Some homework needs to be done on how the cables are constructed when considering a modular power supply.

And when using a modular power supply, adapters or splitter, make very certain that the connection between both interfaces is secure, firm and flush. Make sure all of your connectors are fully seated. This goes for standard power supplies and the connections you make to the motherboard, your drives, etc. as well. Because if you have a connector that is not fully seated, you create resistance. That resistance not only can cause a drop in voltage at the end of that particular wire, but also create heat. I?ve actually seen BURNT connectors from cables not being plugged all of the way into their sockets.

One last thing; Gold plated contacts. They don't do any good unless they're interfaced with gold plated connectors. In fact, the mating of dissimilar metals is actually more prone to corrosion than if both connectors were tin. So if you get a modular power supply with gold connectors, keep in mind that it may be better to have gold only on the power supply side where the modular interfaces are also gold plated, but not on the component side. I haven't seen hard drives and motherboards with gold plated power connectors.

UPDATE: In PC Power and Cooling's "Power Supply Myths exposed" they state that "the voltage drop can be as much as would occur in 2 feet of standard wire." Actually, two feet of wire don't present much resistance. But they do make the point that they may "can easily loosen, corrode, and burn." That should read, "corrode or loosen and burn." Fears of corrosion are rather unrealistic. A power supply connector has as much chance of corrosion as any other contact point in your PC. Your video card? Your RAM? Even the connectors to your drives, motherboard, etc. Obviously, when you double the number of connectors you double the chance of corrosion, but unless you live on a House board, corrosion is rare. The loosen and burn I explain. Solution: There's no reason to keep unplugging and re-plugging your power connectors. Make sure they're in tight and leave 'em alone.

 

[BloodTravis]

What is the most efficient power supply out, not necessarily the most high powered??

 

[jonnyGURU]

Picking the right power supply

Power Factor Correction:

The Power Factor of an AC electric power system is the ratio of the ?real power? to the "apparent power."

(Paragraph from Dan's Data) Power factor correction (PFC) is, essentially, what you do to complex AC loads (such as PC switchmode power supplies) to make them act more like simple loads (such as toasters).

There are two types of PFC, Active PFC and Passive PFC. This PSU has active PFC. Active PFC uses a circuit to correct power factor, Active PFC is able to generate a theoretical power factor of over 95%. Active Power Factor Correction also markedly diminishes total harmonics, automatically corrects for AC input voltage, and is capable of a full range of input voltage. Since Active PFC is the more complex method of Power Factor Correction, it is definitely more expensive to produce an active PFC power supply.

Passive PFC uses a capacitive filter at the AC input to correct poor power factor. Passive PFC may be affected when environmental vibration occurs. Passive PFC requires that the AC input voltage be set manually. Passive PFC also does not use the full energy potential of the AC line.

In some parts of the world, customers of the utility companies are actually charged more for poor power factor. In the EU, you are simply not allowed to use an electronic device with a complex AC load without any kind of correction! So certain inexpensive power supplies are simply not available over in Europe.

Despite being more efficient for your electric company, power factor may be less efficient to your power supply! The components used to correct power factor generate heat. Naturally, this heat didn?t come from nowhere. It?s using, and wasting, electricity. Furthermore, the heat being introduced to the other components of the power supply causing them to run hotter and therefore less efficient.

Bummer.

This is why you?ll sometimes see certain models of power supplies available in the US with no PFC and available in the EU with PFC, but only capable of accepting a 230V input. Remember what I said about power supplies running more efficiently at 230V than they do at 115V? Same rule still applies here. The power factor correction circuitry isn?t going to get as how with 230V coursing through it as it would with 115V because the amperage is going to be lower.

 

[jonnyGURU]

Originally posted by: AMDUALY
Good read. ::thumbsup:: Very in depth.

Thank you.

Originally posted by: BloodTravis
What is the most efficient power supply out, not necessarily the most high powered??

Probably a PCP&C 1KW if run around the neighborhood of 300 to 850W Should be about 85% at < 50C.

Second would be the Seasonic SS-400HT at around 300W. That's right at 85% at that wattage as well. The Seasonic has a few peaks in valleys in it's efficiency, though. But it costs 1/5 as much as the PCP&C.

Of course, I'm far from "all knowing" so I may be wrong.

There's a lot of good power supplies out there at different efficiencies. And the difference between one and another can be 75% and 85%. In reality, if your load is 300W, that's only a difference of 400W at the wall and 355W. Not a HUGE difference.





I'm going to take a little break. My fingers are tired from typing.

 

[rise]

nice work man :beer:

i've been eying one or two of those seasonic 400ht's. it would make a significant difference to me as i run DC projects 24/7 on my two machines.

i'm just not sure it would be enough for my main rig, in sig. my sons rig should be fine as it only has a x300 and everything is at stock.

my apc utility shows my main rig pulls 300w from the ups when running dc projects and 360ish when adding a game or some load on the gtx. my vcore is only 1.44v on the overclock.

you think that 400htt would suffice for long term 24/7 use? or is that pushing it?

 

[jonnyGURU]

Originally posted by: rise4310
nice work man :beer:

i've been eying one or two of those seasonic 400ht's. it would make a significant difference to me as i run DC projects 24/7 on my two machines.

i'm just not sure it would be enough for my main rig, in sig. my sons rig should be fine as it only has a x300 and everything is at stock.

my apc utility shows my main rig pulls 300w from the ups when running dc projects and 360ish when adding a game or some load on the gtx. my vcore is only 1.44v on the overclock.

you think that 400htt would suffice for long term 24/7 use? or is that pushing it?

Replace the fan or bypass the fan controller and it would run forever.

 

[rise]

cool, i ordered one so i'll see how it goes. what kind of fan do yorecommend for it? i thought it had a pretty good adda fan already?

 

[jonnyGURU]

Originally posted by: rise4310
cool, i ordered one so i'll see how it goes. what kind of fan do yorecommend for it? i thought it had a pretty good adda fan already?

Adda is a good fan.

I guess I should have been more clear.

Seasonic uses the advantage of being more efficient as an excuse to run a slower fan and therefore quieter fan. If you could actually move more air through the power supply with a fan that moves more CFM, which is going to be potentially louder, then you're going to prolong the life of the power supply.

 

[rise]

ahh, point taken. thanks again. :beer:

 

[jonnyGURU]

Handy power supply related links:

ATX12V Power Supply Design Guide
Extreme PSU Calculator
How Stuff Works: How PC Power Supplies Work
Many Different Connector Pinouts
Ohm's Law Calculator and Formulas
PFC Decoded
Power Supply and Chassis Chapter from Upgrading and Repairing PC's
UL Online Certification Database Seach
UL's Complete Database of Power Supplies
Wikipedia Entry for SMPS
World Electric Guide (V, Hz and Plug Types Around the World)
PSU Inquisitor

 

[GalvanizedYankee]

There's the fan rise, near the bottom of the page http://www.silentpcreview.com/article261-page2.html

Given you might find more cfm with less dBA in a sleeve bearing fan, I think it would be wise to stick with a ball bearing fan because they do tolerate heat better.

Just a thought

__________________________________________________________________________


Good work and thanks for the thread..:thumbsup:

Ahhhh Links.

...Galvanized

 

[starwars7]

Hey jonnyGURU, this is an awesome post!!! Your write-up was great!.

One question, I've been to your site before and was wondering when you last updated your ratings of different PSU Manufacturers?

I guess I was surprised by FSP's position in the rankings, figured it would have been up with Antec.

Thanks!

 

[jonnyGURU]

Originally posted by: GalvanizedYankee
There's the fan rise, near the bottom of the page http://www.silentpcreview.com/article261-page2.html

Given you might find more cfm with less dBA in a sleeve bearing fan, I think it would be wise to stick with a ball bearing fan because they do tolerate heat better.

Just a thought

__________________________________________________________________________


Good work and thanks for the thread..:thumbsup:

Ahhhh Links.

...Galvanized

True. But sleeved bearings are quieter and still have a five year life span (about as long as the life of a PSU.) Yeah, they're more succeptable to shorter lifespan due to heat, but as long as there's enough air moving through the PSU, I'd use a sleeve bearing.

Originally posted by: starwars7
Hey jonnyGURU, this is an awesome post!!! Your write-up was great!.

One question, I've been to your site before and was wondering when you last updated your ratings of different PSU Manufacturers?

I guess I was surprised by FSP's position in the rankings, figured it would have been up with Antec.

Thanks!

I've got to update that damn thing. That's why I haven't copied and pasted or linked it here. It's in need of updating. I also need to update my "make-shift calculator" to include nVidia 7800 and ATI X1700 and X1900 cards.

 

[starwars7]

Originally posted by: jonnyGURU

I've got to update that damn thing. That's why I haven't copied and pasted or linked it here. It's in need of updating. I also need to update my "make-shift calculator" to include nVidia 7800 and ATI X1700 and X1900 cards.
[/quote]

So do you have a feel for what color FSP (with FSP part number) would fall under in your new ranking?

Right now I'm looking at the Enermax Liberty ELT400AWT and the Sparkle (aka FSP) FSP550-PLG-SLI 550W. Those are the two that I like most in the $80 range (my budget). I Don't plan to use SLi, but if the Sparkle/FSP brand is close to Enermax I figure might as well have the option.

Thanks!

 

[jonnyGURU]

Originally posted by: starwars7

So do you have a feel for what color FSP (with FSP part number) would fall under in your new ranking?

Blue. I'm not really sure why I initially put it where I did. Probably because when I wrote that FSP was a little behind with properly load distributing a power supply for use with a modern system.

 

[starwars7]

Originally posted by: jonnyGURU

Originally posted by: starwars7

So do you have a feel for what color FSP (with FSP part number) would fall under in your new ranking?

Blue. I'm not really sure why I initially put it where I did. Probably because when I wrote that FSP was a little behind with properly load distributing a power supply for use with a modern system.

Didn't take you long to update your site

Thank you for the info! With that in mind, if the Sparkle FSP550-PLG-SLI had dual 12V I think my decision would be cake. But I'm still on the fence about dual 12V's importance in the longrun.

 

[jonnyGURU]

Originally posted by: starwars7

Didn't take you long to update your site

Dreamweaver, man. Open, edit, save, "put" (built in FTP.) Doesn't get any easier.