telecomguy9 Posted May 6, 2004 Share Posted May 6, 2004 I'm building a new computer and am wondering about power needs. How can you determine what wattage power supply is needed? What is it dependent on? Any help would be great. Thanks. Quote Link to comment Share on other sites More sharing options...
GolfProRM Posted May 6, 2004 Share Posted May 6, 2004 Essentially your needs are based on your Processor and the amount of devices inside your machine.If you're running a basic system (one processor, average video card, one harddrive, one CD-rom, 1-2 PCI cards) - you won't need much of anything more than about 300W.If you're talking multiple harddrives, multiple CD roms - or anything else exotic, you'd want more... The good news is you can't "over-do" it... anything rated to run higher won't be affected if it's not pushed hard Quote Link to comment Share on other sites More sharing options...
ross549 Posted May 6, 2004 Share Posted May 6, 2004 A bit of advice about power supplies.....What you pay is what you get. If you get a $20 powersupply, don't expect it to do much. However if you get a really good one (Antec PC Power & Cooling, etc.) you will have a power supply that will outlast probably two computers. Quote Link to comment Share on other sites More sharing options...
teacher Posted May 6, 2004 Share Posted May 6, 2004 My last school bought me new computers every year. However, the outfit that built them did not put quality power supplies in them. It got to the point where I put tags on the computers to keep track of which ones had died and been replaced. After they had replaced 10 of them they finally pulled the rest and replaced them rather than deal with the collateral damage. They sold enough computers that I think part of why they closed their doors and went bankrupt was replacing so many power supplies. I have learned to go for a quality, higher wattage power supply every time. I do not skimp on power supplies nor on fans.Julia Quote Link to comment Share on other sites More sharing options...
NRD Posted May 6, 2004 Share Posted May 6, 2004 Judging your power supply needs by max wattage is usually not a good idea. You should also take into account how the power is delivered to each rail 12v 5v & 3.3v. A 400 watt PS that only delivers 12 amps to the +12v rail is probably inadequate for most of todays systems.The firing squad has a pretty good article on the subject.http://www.firingsquad.com/guides/power_su...ply/default.asp Quote Link to comment Share on other sites More sharing options...
telecomguy9 Posted May 6, 2004 Author Share Posted May 6, 2004 Wow, that's a lot of info. I asked about the power supply because I'm going to buy a new case and want to get one that comes with a power supply. Here is what I'll have in the case:ChainTech NForce2 Ultra400 400/333/266 FSB/Dual Channel, and Athlon XP 2600+ (Barton), 2 sticks of Kingston 256MB/400MHz DDR RAM, an ATI Radeon 9600 Pro/128MB, two EIDE hard drives and maybe a USB item here, a single PCI item there.I'm guessing the power supplies that come with some of these cases are cheap (probably the cheap cases). Sound right? Quote Link to comment Share on other sites More sharing options...
NRD Posted May 6, 2004 Share Posted May 6, 2004 For the most part, the included power supplies are junk, especially on the pre-modded cases (windows neon lights etc) They have to cut costs someplace, and its usually in the thickness of the case material and Power supply.I'm building a system with a very similar config as yours, and I chose the antec SLK3700AMB http://www.antec-inc.com/us/pro_details_en...hp?ProdID=93700I hope it works out...it has some pretty good reviews, and fits in my budget. Quote Link to comment Share on other sites More sharing options...
ross549 Posted May 6, 2004 Share Posted May 6, 2004 Here Is a good power supply. I have also heard good things about this company. Quote Link to comment Share on other sites More sharing options...
telecomguy9 Posted May 9, 2004 Author Share Posted May 9, 2004 (edited) Hey guys, I've figured out my power consumption needs from this site:Choosing the right power supply From this article I've figured out that my wife's PC's power supply needs on each rail are as follows:3.3v rail - 6amps; 5v rail - 15 amps; 12v rail - 6 amps.I've started looking at power supplies at newegg.com and it honestly looks like the cheapest one they have will supply her setup with all of the power it needs to each rail. Here are her specs:Athlon XP 2000+ CPUMobo w/integrated devices3 fans512MB DDR RAMAGP Graphics card2 IDE drivesCD-RWFloppy driveKeyboardMouseUSB thumb driveUsing that site I added up the estimated current consumption going over each rail and those are the figures I came to (rounding up).If you go to this page:http://www.newegg.com/app/ViewProduct.asp?...n=+&Order=priceYou can see that the first power supply meets my needs, at least from the estimated current consumption perspective. I know the cheapest power supply isn't necessarily going to last long, but I want to make sure that I'm not going crazy and that these figures and what I've found are correct. Maybe I'm missing something, as the first power supply is only a 250W power supply. Any help would be great. Edited May 9, 2004 by ross549 Quote Link to comment Share on other sites More sharing options...
b2cm Posted May 9, 2004 Share Posted May 9, 2004 You should get a better PSU to save yourself hardware nightmares. Quote Link to comment Share on other sites More sharing options...
nlinecomputers Posted May 9, 2004 Share Posted May 9, 2004 I've been servicing computers for over 10 years. One the most overlooked items is a PSU. Most people use price as the main purchase point and they get stuck with a poor unit that will fail. A PSU that fails can take out other units so above all other components a PSU should be the best you can buy. It will safe you grief later on.A good page with info on choosing PSUs is:http://www.directron.com/psu.html Quote Link to comment Share on other sites More sharing options...
Stryder Posted May 9, 2004 Share Posted May 9, 2004 I completely agree with Nline. I have ran across soooooo many PCs where people go cheap (or get cheap power supplies from a PC vendor) on a power supply and it comes back to bite them in the butt. Everything in your PC is dependant upon your power supply, it is the one place you do not want to go cheap. The price difference between a cheap power supply and a good one is less than $25. It makes no sense not to get a quality power supply.On a side note, I build and sell about 100 to 150 computers a year. I use nothing but Antec power supplies. I have never had a issue with any PC I have built where the power supply has been a problem. Quote Link to comment Share on other sites More sharing options...
telecomguy9 Posted May 9, 2004 Author Share Posted May 9, 2004 Thanks for the help, guys. I will look into better manufacturer's and higher wattage, all the while making sure the rails amps are more than enough. Quote Link to comment Share on other sites More sharing options...
-ct- Posted May 9, 2004 Share Posted May 9, 2004 http://www.jscustompcs.com/power_supply/this will also help you decide just how much power you needin my case i need close to 550w due to all the devices i have (6 hdd, 2cdrom, radeon vid card, 4 LED fans, 4 CCD, and the hs/f), but on reccomendation i bought a thermaltake purepower 480w psu (in black) and the system is perfectly fine, quite stable now Quote Link to comment Share on other sites More sharing options...
b2cm Posted May 9, 2004 Share Posted May 9, 2004 Very good link CT. The power requirement estimates look more realistic. I'd also put at 90% as effective of ratings supplied by vendors for their PSUs. Quote Link to comment Share on other sites More sharing options...
Ed_P Posted May 9, 2004 Share Posted May 9, 2004 Wow!! Nice link indeed -ct-. Thanks. Quote Link to comment Share on other sites More sharing options...
Cluttermagnet Posted May 10, 2004 Share Posted May 10, 2004 Thanks for the good link, ct. Looks like my P4 computer is not taxing my cheapie 400W supply very much. The early estimate has me at about 233 watts. This is a tool well worth bookmarking, as it really simplifies the arithmetic. Neat! Quote Link to comment Share on other sites More sharing options...
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