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Is the powersupply the most complicated part to buy??

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April 25, 2006 8:58:19 PM

I'm pretty familiar with PC Components and I'm pretty good on knowing the difference between the good and the bad, but when It comes to power supplies, I can't understand it

What makes a 480w Thermaltake better than a 600w Generic???
How many "cords" should they have?? does it mater? are all PSU the same?

I built many computers with Cases that come with the PSU, and they all worked fine, I have a Pentium Prescott 3.4ghz with a Nvidia X700 256mb, 2 160gb Barracudas, 1gb of ram and it has a cheap PSU and it has been working fine for years.

So my question is:

Considering I'm not going to overclock my system. Does it make a difference If I spend $20 on a 480w PSU from Logisys, or $60 on a Thermaltake ?

thanks
April 25, 2006 9:34:19 PM

No that would be budgeting your money and getting the best of it when it comes to buying computer parts. Anyways if you want a good psu then get one from Antec and Coolermaster, preferably higher wattage for they provide plenty of power and stability.
Related resources
April 25, 2006 10:15:52 PM

Unfortunately power supplies are one of the last things many people pay attention to. What separates a good PSU from a bad PSU is reliabiity.

The basic general rules are as follows:

1. The PSU should cost at least $40. Less if it's on sale. More for higher wattage.

2. Is it heavy for it's size? Good PSUs tends to be heavy because they use bigger components like a larger heatsink.

3. Do not buy a PSU for that flashy blue LCD fan.

Those are the rules you should follow if someone just dumped a bunch of unmarked PSUs on your head.

How can you find out how reliable a PSU is? Reviews. Not just any reviews, but reviews from hardware site. Don't take people's opinion at face value, even mine, and don't base it on user reviews from Newegg. User reviews are good to find out what the general consensus is, but that far from actual hardware insight.

Hardware review sites:

SilentPCReview

PCStats.com

ExtremeOverclocking.com

Systemcooling.com

A good primer is this article:

Power Supply Fundamentals & Recommendations

Okay, anything else other than reliability that makes a PSU good? Yep, efficiency is one. Cheaper PSU tends to have lower efficiency (65%) while more expensive ones will have higher efficiency (80%+). What does that mean? Let’s say all the components in your PC draws 200 watts by measuring the power coming out of your PSU. That will be lower than the amount of power being drawn by the PSU. It is less as a result of conversion from AC to DC. This result is heat that gets dumped into the case making the PC technically harder to cool. A 65% efficient PSU delivering 200 watts of power will be drawing 307.7 watts from the AC outlet. An 80% efficient PSU will draw 250 watts from the AC outlet. There are some PSUs that can peak at 85% efficiency which drops the draw down to 235.3 watts.

Another aspect of PSU people tend to ignore is it’s acoustic characteristics. A PSU has a 120mm to many that means they are all going to be loud. Right? Not exactly. Cheaper PSU have a greater tendency to be louder than a more expensive one because of cost cutting. But even expensive PSUs can be loud. So which PSU are quiet? Read the reviews.

Other factor is if the PSU is modular. That means instead of the molex wires being permanently attached to the PSU, modular PSUs have removable wiring so if you have a couple of molex wires you are not using just disconnect them and store them away. That’s great for wire management. But I read a short blurb that modular PSUs have certain issue. What are those issues? I don’t know, I didn’t read the review / article.

Aren’t you glad you asked?

In my opinion the one of the best PSU on the market is the Seasonic S12 series. They are efficient, quiet, and reliable. Don’t trust me? Then read the reviews.
April 25, 2006 10:27:53 PM

no to hard just need to make sure you have one that fits your needs. For example if you wan to SLI then you need a SLI PSU
April 25, 2006 10:48:49 PM

Thank you, great info. So for this system what would you recommend?

AMD Athlon64 3700+
Asus A8N5X
2x1GB DDR PC3200
300GB Seagate SATAII
ATI Radeon X1800XT
DVDRW 16x (only one drive)

would an Enermax 460w do the job? Is it a good pick? what do you suggest under $70??


thanks
April 25, 2006 11:07:44 PM

There's a lot of hysteria concerning power supplies, and a lot of bad/wrong information. You want a good one, yes, but too many people spout too much wrong information when a PS in concerned, mostly because they just parrot what they read on the internet [gasp] without knowing what they're talking about.
April 25, 2006 11:12:49 PM

enermax are a good make, im using there 600w SLI ready noisetaker at the moment. that 460w should be fine as long as you dont go SLI /crossfire... another thing to note dont always go off the wattage, read how many amps are on the 12v rail more amps the better.
April 26, 2006 12:04:20 AM

Quote:
Thank you, great info. So for this system what would you recommend?

AMD Athlon64 3700+
Asus A8N5X
2x1GB DDR PC3200
300GB Seagate SATAII
ATI Radeon X1800XT
DVDRW 16x (only one drive)

would an Enermax 460w do the job? Is it a good pick? what do you suggest under $70??


thanks


Yes, it should be fine.

This actually touches upon one thing I didn't even mention in my post. In modern PSU what matters is not the total wattage, but the amprage on the 12v rail. The 12v rail powers just about everything on the PC which includes (but not limited to) the motherbaord, CPU, GPU, Fans and drives. Hard drives and DVD-ROMs run off of the 5v and 12v line, or just the 5v depending on the PSU used.

Anyway you are looking for something with good amp on the 12v line. A typical 460w PSU will probably have around 26 - 30 amps. That means it can deliver 312 watts to 360 watts. That power goes to the the components I mentioned above. The two biggest power draws are the GPU first, and the CPU second.

A non-overclocked X1800XT has been measured to consume 103 watts of power.

A non-overclocked Athlon 64 3800+ has been measured to consume 60 watts of power. The 3700+ should consume slightly less.

Under full load they both draw 163w from the available 312w on the 12v line add 75w for overclocking and safety margin, that brings it up to 233w. That leaves you 79w left to power everything else which is enough.

Note: As you may have noticed in the GPU link, the competing 7800GTX consumes 81w (not overclocked).
April 26, 2006 12:28:17 AM

Quote:
The basic general rules are as follows:

1. The PSU should cost at least $40. Less if it's on sale. More for higher wattage.

2. Is it heavy for it's size? Good PSUs tends to be heavy because they use bigger components like a larger heatsink.

3. Do not buy a PSU for that flashy blue LCD fan.

very technical explanation huh?

i noticed people here pay more attention to the PSU than to the quality of the energy provided to your PSU, i.e the energy that comes from your outlet. A $70 wont help if connected directly to an ungrounded, unstable power outlet.

i'd risk to say that yes, if you use a generic $20 600W PSU connected to some kind of UPS, energy conditioner or something will work flawlessly for years...
April 26, 2006 12:47:54 AM

Quote:
The basic general rules are as follows:

1. The PSU should cost at least $40. Less if it's on sale. More for higher wattage.

2. Is it heavy for it's size? Good PSUs tends to be heavy because they use bigger components like a larger heatsink.

3. Do not buy a PSU for that flashy blue LCD fan.

very technical explanation huh?


You left out the next sentence:

Quote:
Those are the rules you should follow if someone just dumped a bunch of unmarked PSUs on your head.



Quote:

i noticed people here pay more attention to the PSU than to the quality of the energy provided to your PSU, i.e the energy that comes from your outlet. A $70 wont help if connected directly to an ungrounded, unstable power outlet.


True but I don’t think people would like if I said to add in a $500 - $1,000 AC Power Line Conditioner to insure that the PC will receive an average consistant voltage of 118v and noise free current.
April 26, 2006 1:03:44 AM

hmmm i dont know about prices for a ups or line conditioner in the US, but where i live a good line conditioner costs like 20 dollars. A 700VA UPS which keeps your computer running for about 15 minutes without energy (enough time to save and close all your apps) costs about 100 dollars.

I think it's a good investiment even if it costs $500 coz it protects you current and future computers. and a line conditioner is something you buy just once in your life
April 26, 2006 1:24:35 AM

Quote:
hmmm i dont know about prices for a ups or line conditioner in the US, but where i live a good line conditioner costs like 20 dollars. A 700VA UPS which keeps your computer running for about 15 minutes without energy (enough time to save and close all your apps) costs about 100 dollars.

I think it's a good investiment even if it costs $500 coz it protects you current and future computers. and a line conditioner is something you buy just once in your life


UPS and Line Conditioners are two separate hardware equipment. The line conditioners I'm referring to are those used for audiophile equipment. High end audio equipment (amps, prepro, etc) and speakers will immediately let you know if you have a bad line 'cause you'll be able to it, if you have an ear for it.

By audiophile system I mean something that will cost you at least $6,000 to build. That's actually considered an entry level audiophile stereo system.
April 26, 2006 1:58:49 AM

You know this is why I love THG. About the time I was looking to totaly rebuild my comp, they did the PSU stress test. Now that was a deal sealer for me. FSP Group Epsilon 600W passed every test and is whisper quiet. I will admit it came at a premium ($155) but when its SLI certified, loomed, quiet, powerful, and passes a mad stress test, then I will shell out for it. I care because I run my rig 24/7 under load so its rather important to me to have a stable PSU.

Best advice is read reviews (as many have said already), then go somwhere else and read another review. PSU's are very strange components which I will admit to barely understanding, but when I read a review it at least bring is it down towards my level so I can comprehend what all the crap it does. lol :p 
April 26, 2006 2:41:07 AM

Quote:
By audiophile system I mean something that will cost you at least $6,000 to build. That's actually considered an entry level audiophile stereo system.


Not sure where you came up with that price, but one can assemble a VERY good-sounding system for half that price. Just like gaming computers, the proof is in the performance of the assembled rig. My own stereo system did cost more then the $3K price I elude to, but I've been doing this for a long, long time and it's grown in proportion to my gut. But I recently put together a great-sounding system for a friend that came in under 3 grand. We did shop around quite a bit and got a great deal on the speakers. We made the stands for the satellites and made tiptoe-like feet for the sub and the satellite stands. This system sounds SO good, it had me frowning at my own beast for costing so much.
April 26, 2006 8:38:56 AM

Can any1 give me a suggestion under $70? and also one under $50/40, thanks
April 26, 2006 12:31:52 PM

This would be a minimum to handle your setup.

SPARKLE ATX-350PN-B204 ATX 12V 2.0 350W
+3.3@22A,+5V@21A,+12V1@18A,+12V2@16A,-12V@0.3A,+5VSB@2.0A
$39 shipped


This would give you a nice margin for upgrades, like more fans / hdd / dvd etc...

SPARKLE ATX-400PN-B204 ATX 12V 2.0 400W
+3.3@30A,+5V@28A,+12V1@18A,+12V2@18A,-12V@0.5A,+5VSB@2.0A
$51 shipped

SPI is nice, inexpensive quality unit - good components. We use them for 2U field network of rack mount linux appliance builds, extremely reliable - no DOAs that I know of.

edit - the directron link I mentioned says SPI is quality "weight" manufacturer...
April 26, 2006 2:40:01 PM

Quote:
There's a lot of hysteria concerning power supplies, and a lot of bad/wrong information. You want a good one, yes, but too many people spout too much wrong information when a PS in concerned, mostly because they just parrot what they read on the internet [gasp] without knowing what they're talking about.


What pain says is true to a certain extent, but note that he doesn't provide any real helpful information.
April 26, 2006 3:08:51 PM

Quote:
Can any1 give me a suggestion under $70? and also one under $50/40, thanks


Under $70 I would recommend the following:

FSP Group (Fortron Source) AX450-PN - $58 shipped

COOLER MASTER Real Power RS-450-ACLX - $67 Shipped

Under $50?

XClio 450BL 450W Power Supply - $51 Shipped

Okay, so it's $1 over 50 bucks, but you never said if that was with or without shipping. I actually never heard of this company but after scanning through a hardware review of it, it seems to be a good PSU for such a low price.
April 26, 2006 3:31:14 PM

Quote:
There's a lot of hysteria concerning power supplies, and a lot of bad/wrong information. You want a good one, yes, but too many people spout too much wrong information when a PS in concerned, mostly because they just parrot what they read on the internet [gasp] without knowing what they're talking about.


What pain says is true to a certain extent, but note that he doesn't provide any real helpful information.

And your comment to me, does? I was making a comment, nothing more. I see a lot of general banter around the forums, so I guess I didn't know the rules were that you had to give specific details, right or wrong, in every posted message. At least I stayed on topic. :!:

You said yourself to read reviews and not listen solely to internet opinions, so I guess there's really nothing more to add.
April 26, 2006 3:38:32 PM

well, i can see some helpful information:

dont buy just because other people say so

on the other side, i think is totally useless comments like:

your psu is a crap, buy a brand name 500W

wtf is a brand name psu? every psu has a brand name. and often the suggested power is way over the user needs
i still think that people should invest on the quality of the energy provided to the psu, doing a good grounding job, using a voltage regulator, things like that.
i ALWAYS used generic cheap psu's WITH a quality AVR and i never had any psu or component burned/damaged.
i'm not recommending going to a generic psu if you can buy a quality one for cheap... but buying a 550W just because someone says is completely stupid. buying a well dimensioned psu with a good AVR and grounding system is wise. And will last longer than the psu alone.
April 26, 2006 7:38:13 PM

Quote:


your psu is a crap, buy a brand name 500W

wtf is a brand name psu? every psu has a brand name. and often the suggested power is way over the user needs


Yes, it is true the suggested power is usually way over the user’s needs. But as a business the video card companies have to cover their bases because they don’t know if people have an Athlon 64 or a Pentium 4. Athlons uses less power than a Pentium 4, but video card sellers always play it safe and recommends a PSU with a lot of power so that they will not be liable in a class action lawsuit if PCs are damaged because too much power is being drawn from a weak PSU.

A video card company has the following choices to put on the box:

1.This video card requires a minimum of XXX watts.

or

2. Use this video card at your own risk.

As always I try to include links in all my post when I recommend a power supply.

These are the links I provided in one of my posts above

CPU:
CPU Power Consumption.

GPU:
GPU Power Consumption.

And as I stated before, it is always better to do your research on a PSU rather than relying on someone else’s recommendation. That’s why I listed 4 hardware sites that review power supplies in my above post. It’s one thing for me to simply say the Seasonic S12 series are excellent, but expensive PSU. It’s quite another to actually read that at several hardware review sties that puts power supplies through a barrage of tests.

It’s easy for people who know or can estimate how much power each component uses to determine exactly how much power a system uses. For others who don’t know or don’t care it’s better for them to simply get the recommended minimum PSU requirement.

Regarding brand names. Okay, how about “Recognized Brand Names”. Better? Kinda like comparing blue jeans, do I want to buy Levis or Great Plains? Both are name brands, but Levis is more well known. Or comparing cars, you have the money to buy a Ford or a Mercedes. Which one to choose?

Quote:


i still think that people should invest on the quality of the energy provided to the psu, doing a good grounding job, using a voltage regulator, things like that.



It’s always good to ensure constant and clean amperages and voltages. Most people don’t do this, the exception are usually audiophiles who wants to protect their audio system that costs several thousands of dollars to build.

Quote:


i ALWAYS used generic cheap psu's WITH a quality AVR and i never had any psu or component burned/damaged.
i'm not recommending going to a generic psu if you can buy a quality one for cheap



This is merely a point of view; which is the opposite of my point of view. In between will be the mainstream point of view for people who will buy average products at a good price. Not too cheap. Not too expensive.
April 26, 2006 9:02:20 PM

yeah... i'm glad you think and advice people the way you did
but one thing that makes me mad at this forum is that every single problem, since a stuttering computer, a non-posting one, to a freezing one... the first thing people always say: buy a new psu coz the one you have is no good. They dont even tell the guy to test something, or to try to find the cause of the problem... they only say: buy a new psu.. i wonder if they get profit on advertising psu or something
April 30, 2006 12:14:42 AM

Is it bad to have a power supply that is too powerful for my PC?

I have the following PC:

Athlon 64 3400+ socket 754 (i think)
ASUS K8N-E
radeon x700
1GB of RAM
Maxtor 80 GB hard drive
Sony DVD burner
Soundblaster Live
Power Supply 400

I'm thinking about upgrading to AM2 when it comes out. I might get the nvidia 7900GT as well. Do you think my power supply should be upgraded? If so, how much power do you think I need to buy?

Is it worth buying a 500w power supply for less than $50 or should I look at ones costing less than $100?
April 30, 2006 12:26:57 AM

If you plan on going AM2 with a 7900GT you will probably want a beefier PSU. The problem with the Sub $50 ones is the distribution of power. ALmost everythign is run off the 12v rails so if you have 400W on a 3v rail it won't help you. You can get a decent PSU for $70 or so that will do you fine as long as you don't go SLI. If you think about going SLI then it becomes a little more complicated.

Check out the name brands like Seasonic, Enermax, FSP Group in the $65-80 range and that should put you in a good position to upgrade. I'd say about 500w will do you just fine. 400w seems a bit thin depending on rail ratings.
April 30, 2006 1:03:42 AM

Well, I know an extremely good company, an overclocking PC Builder, who ships 7800GTX 512 OC'ed SLI'ed with FX-60's at 3.0GHz on stock AMD cooling who uses Ultra X-Connect 500W... So wattage isn't always everything and this PC is stressed, and I mean stressed to it's limits.

~Ibrahim~

Company:
http://www.overdrivepc.com/
April 30, 2006 5:38:46 AM

It might be possible depending on how many amps are on the 12v rail. If there are two listed on your power supply (PSU), you may need to take it out, then simply add them together.

The good news is that a non overclocked (OC'ed) 7900GT uses about 52w of power, so it is only about 20w more than the X700. Below is an article with actual power measurements. The 7900GT is not listed, but it uses about 5w - 8w less than the 7800GT because it uses the 90nm die instead of the 110nm die which shrinks it down and uses less power.

GPU Power Consumption

It's too early to tell how much power a Socket AM2 CPU will use especially since you didn't list which one you want to buy.
!