Building my own PC - why different wattage for power supplies?

[OlympusMons]

Hello all. This is my first post.

My old faithful Dell Win2k machine I bought in April 2001 finally has died. I've decided to build my own PC from scratch and in the meantime, I'll be using my laptop. I'm not a hardware techie (I'm a programmer) so I imagine I'll have a lot of question regarding hardware as I build my system.

Why are power supplies offered in various wattages and what is the deciding factor when chosing one? Is it simply, the higher wattage PS you buy, the more components it can power? What's "the industry standard" wattage output? Why someone buy a 350w or a 500w power supply?

THANKS!

 

[fishstickz]

Wattage isn't really a requirement. While the rule that more wattage = more components generally applies, you will be much more interested in the amps that the different rails of the PSU carries.

This link will give you all the revelant information you need:

Power Supply Guide

Personally, I would aim for a PSU between 400-500W for a normal desktop system, but refer to that link for further details.

 

[Jeff7]

For a basic system, a quality 300W power supply will be quite adequate. I like Seasonic power supplies - they are made to be more efficient than other brands, and they're quiet.

They may be more expensive than generic things, but a power supply is not something you want to skimp on. You don't want to feed yourself stuff you scrape off the floor of a restaurant just because it's cheaper. Same with a computer - don't feed it junk power. A power supply is a component that will last a long time too - it won't be getting upgraded constantly, like maybe a hard drive or videocard.

Example - I've got a 460W Seasonic running:
Athlon XP-M 2100+ running at 2.1GHz
NF7-S rev2.0
Radeon 9500
5-6 7200 rpm hard drives
DVD+/-RW drive
TV tuner

Its power consumption when the CPU is under load with 5 hard drives spinning? 190.4 watts. So heck, the right 300W power supply might even be able to run that system.
A basic system with only one or two hard drives will not use near that.

 

[furballi]

Which method are you using to achieve 190.4 watts?

 

[d2arcturus]

Originally posted by: furballi
Which method are you using to achieve 190.4 watts?

That's how many watts his system is using while 5 hard drives are spinning and the CPU is under load.

All of these brands: Antec, Seasonic, Fortron, OCZ, Enermax (all I can think of) make reliable power supplies. You should be fine with a 350-400W PSU, and if you're installing high-end compnents then you'll want about 400-500W. 500-600W is really only for OC buffs and rich people with SLI.

 

[DanDaMan315]

Well PSU companies (and people) will tell you that you need a much higher wattage PSU than you really need. My friends gateway (2.4 northwood + gf4) was running on a 160w PSU which dumbfounded me. I would suggest a PSU around 350w.

Are you going to use your old component like DVD/R and HD?

 

[OlympusMons]

Originally posted by: DanDaMan315
Are you going to use your old component like DVD/R and HD?

Thanks everyone. I will be building this unit from the ground up. No recycled parts.

 

[wpshooter]

Don't skimp on the power supply, buy a good one, more is better than less. For "MOST" modern day motherboarded & componented systems, a "QUALITY" power supply in the 480 to 500 watt range is sufficient. I prefer ANTEC.

Please note that a few companies (I don't know if ANTEC has went modular yet) have FINALLY started to make MODULAR power supplies (i.e. supply has ports into which you plug only the connecting wirings that your system actually needs). I would highly suggest that you research & buy one of these. It should make the build of your system much easier and better. I have not built a system since the modular power supplies have came out, but I assure you that any systems I build in the future will be using this type of PS.

Go luck.

 

[jpcording]

Ok -- I'm just playing devil's advocate here -- I have a new Thermaltake 430W powersupply in my Newegg shopping cart right now. But a 500W power supply for MOST systems? What about the millions of consumers running generic power supplies at half that and never experience a problem? If you're really talking about MOST systems, if you've got a 350W PSU with a namebrand on it, you're WAY ahead of MOST systems.

 

[wpshooter]

I said it was sufficient. I was trying to say that it is better to have to much "power & quality" (and to leave yourself some room for future growth) than to buy to little and wind up having problems. Yes, probably the big majority of system are running on 350 or LESS, but a big majority of them are not EXACTLY modern or even near cutting edge technology. Why risk having all kinds of problems to save $20 to $40 ? There are all kind of post to be found here where people have spent hours upon hours troubleshooting various problems because they tried to cut corners buy saving a few bucks on less than quality & the grade of components they needed. If you, want a sub-par system you can go to one of the major computer manufacturers and buy one of their $399 "DEALS" and see what happens to most of the system components in sometimes a matter of just a few days or months of operation.

Thanks.

 

[Jeff7]

Originally posted by: furballi
Which method are you using to achieve 190.4 watts?

A little device called Kill A Watt. The power figure there is the amount that the power supply was drawing from the wall. So, let's assume an efficiency of 80% - that would mean that 38.08W was being dissipated in the power supply as heat, leaving 152.32W for the components in the computer.

 

[biostud]

Post what you intend to buy, so w can help you decide how powerfull a PSU you need. There're good and no-name brands, I prefer Seasonic for quietness.
When you think you have what you need don't hesitate to return and get an evaluation here

 

[furballi]

Ok...looks like some type of ammeter. I use an AC ammeter connect in series with the AC line. The average AMD 64 system will pull about 200 watts at full load. Add another 100 watts for a few more hard drives, optical drives, and a high end video card.

A good PSU will provide a stable output voltage at low and high load. Efficiency is also important because an inefficient PSU will run hotter. And heat will DRAMATICALLY reduce the output of the PSU. Note that most PSUs are rated at full power at 25C. The more expensive units is stable up to 40C.

A quality 350 watts PSU that's at least 75% efficient and is rated at full power up to 40C will work in 95% of the rig today. If you have some extra cash, then bump up to the 400 to 500 watts class.

Enermax and Fortron PSUs will give you more value for your $.

A modular design is okay if you're not drawing a lot of amperage on the line. A contact resistance of 0.01 ohm with result in a voltage drop of 0.15VDC at 15 amps.

http://www.3gplaza.com/estore/control/C...r3G/productdetails?id=34336&srccode=PW

 

[OlympusMons]

I'll probably start my shopping process today. Antec looks good but I wish they were a little more stylish. If I'm going to do this, I'd love to have a real stylish techie looking case.

 

[fishstickz]

Consider sleeving the cables (it isn't that hard). It makes your PSU cables look really hot.

Fortran Blue Storm series PSUs are very sexy as well, and come pre-sleeved.

 

[The Pentium Guy]

Get an antec power supply and get a different case.

Coolermaster Cavalier, Coolermaster Wavermaster, Coolermaster Centurion

--or on the more flashy side--
Thermaltake tsunami (if you don't mind going deaf), thermaltake soprano (not as loud), thermaltake Highest Xaser (your ears will blow off with the 7 fans it's got)

--on the more boxy side--
Lian Li PC-60, Lian Li PC-65 (with window), Lian Li PC-75 (HUGE case, with window).

Also Logisys Phanthom is a flashy case that cools well (virtually unrestricted front grill) and is relatively cheap ($55?)

-TPG

 

[The Pentium Guy]

Oh - if you're talking about the POWER SUPPLY not being stylish: Get an OCZ. They're the only "stylish" power supply brand I would trust (aside from the higher end Fortron BlueStorm models).

 

[Cheezeit]

yes, the more watts, the more it can power. But these days, amps matter more. get at least 14a each for dual rail, or 25a for single rail.

definaltely don't buy generic. like people have said, fortron, antec, enermax, ocz, seasonic are good.

my personal reccomendation has always been the fortron blue storm 500. best effciancy, quiet, powerful, from a good company, and it looks awesome with presleeved cables.

 

[OlympusMons]

Hey guys.

It's either going to be the Antec Sonta II or this:

ThermalTake Tsunami

I think I just might buy the Tsunami and insert a good PSU into it. Whatcha think?

It says that it will take ATX or MATX motherboards. Is this OK and it is standard?

Thanks!

 

[Cheezeit]

Originally posted by: OlympusMons
Hey guys.

It's either going to be the Antec Sonta II or this:

ThermalTake Tsunami

I think I just might buy the Tsunami and insert a good PSU into it. Whatcha think?

It says that it will take ATX or MATX motherboards. Is this OK and it is standard?

Thanks!

the sonata2 is better than the tsunami. TT cases are usually loud, and I don't justify getting them unless you really love the looks.

the psu that comes with the sonata is good, too.

most mobos are atx, and some are matx (micro atx) to save space or fit in small cases.

 

[The Pentium Guy]

Might want to downgrade to the Soprano (has 2x120mm fans instead of 3) unless you want to go deaf . Or, buy the tsunami and replace teh fans with quieter ones.

 

[ElFenix]

the reason people started insisting on big watt power supplies is that amd said that you should use a "300 watt" power supply for some of the early athlons. the reason amd said that is because they know that people who build computers are cheap bastards and get some generic "300 watt" power supply that actually has 175 watts