Page 4 - How to Choose A Power supply

yeah ill add it, but its hard for me to easaly change something because i dont have the edit option because my post is old so well each update i gotta contact a mod with the update... but its okay, ima do a big update on it soon

I used eXtreme Power Supply Calculator in order to come up with a number which was 315 WATT. I have a dimension E520 Dell Desktop with 305 WATT PSU. so still it lacks for 10 WATT!! but I thought to myself maybe I should give it a try with new graphic card on the same PSU and see wheter it works or not, the problem is that I don't know what happens if it's not enough powerful for that, I mean is it going to cause damages to the computer or it simply restarts?

Usually it'll just be unstable and reboot a lot, but sometimes the PSU can really go for it and die in most "inelegant" way, hehe, and can sometimes send spikes of voltage down other rails before finally giving up in a blue flash and some smoke. These spikes can kill anything that is connected to the PSU at the time..

So it's not recommended to take a chance on these things if you value your computer

its a dell whats there to value????


Anyways maybe we should get an update on this thread and list

so a weak PSU may cause damages. how about a really strong one?!I mean is it going to be okay for my motherboard or other components to use for example a 600 WATT PSU or there are some limitations for choosing the maximal power of PSU according to the type of the motherboard?

A strong psu is great, well a quality psu. If its a bad psu putting out too high of voltages then it can be very harmful. But a good reliable psu, even if it is a lot more watts then you need it will be fine. Wattages won't hurt your computer, voltages will.

Yeah, a computer will only use what it needs. a 600W PSU won't be shoving 600W into your machine all the time, that'd be insane... It's just capable of giving 600W should the need arise

thanks man! I am a little bit dumb in Electronics!! also I wanna spend money which I have to work for! so I want to be sure about the PSU I wanna buy, here I wrote down the information of my current PSU on my computer which are:

DC OUTPUT : 305 WATT
INPUT: 100-120V~/9A 50-60 Hz
200-240V~/4.5A 50-60 Hz
OUTPUT: +5V ===/22A MAX -12V===/1A MAX
+5V(FP) ===/4A MAX +33V===/17A MAX
+12VA ===/18A MAX +12VB===/18A MAX
COMBINED POWER ON +33V AND +5 RAILS NOT EXCEED 150W.
COMBINED POWER ON +12VA AND +12VB RAILS NOT EXCEED 264W.
MAX CONTINOUS TOTAL DC OUTPUT POWER SHALL NOT EXCEED 305W.

and the diemensions are:
100 (mm) Height*140 (mm) Length*125 (mm) Width
which the case can afford longer Length too.

in the case I want to buy a good OR great PSU which is at least 500W what would you suggest me?

There are a lot of good brands listed at the beginning of this thread. It really depends on how much you want to spend. You can get an antec or enermax for relatively cheap, newegg had (not sure if they still do) an OCZ silentstream on sale, those are great psus.

your PSU doesn't seem to be a too great one. It does work tough , right? . Anyway , It will depend on what are your computer specs. with something like a normal computer , a 400Watt FSP fortron Unit will be more than sufficient. Post up your computer specs. and why do you want to change the powersupply? , are you upgrading.

also my guide is really outdated, I should update it, I updated a while ago on another forum , I could take that one and make a couple of changes and then post it here. I have the week off so I'll probably do that!

This might be moronic, but I'm not clear whether a PSU and a power adapter are the same thing? I bought a replacement 12v adapter from the net but it was confusing because I wasn't sure how to figure out what my amperage needs were. PSU isn't the same thing as a power adapter, right?

No, they are not the same thing. A power adapter is a little cord that has two different connectors on the ends. A Power Supply Unit is the big gray thing that has a cord that plugs into your wall.

I don't know any of this was brought up. I only read the first and last pages. These are only suggestions from what I know and have learned about PSU's over many discussions on the matter from well..former users that have gone on to bigger and better things.

Firstly, I would like to point out that those Wattage Requirement calculators and sites should only be used as a guideline. Personally, I find them of little to no use whenever I build a rig.

Secondly, wattage ratings are not always accurate. This fact was mentioned by snod. Manufacturers all too often put the maximum output rating on the box or label to sell power supplies. As pointed out, these ratings can be determined anywhere from room temp to zero degrees. The industry doesn't (at least to my knowledge) have any regulation or standard on determining the wattage ratings. So, you could be buying a PSU that says 600W MAX on it that would never reach 600W output in the vacuum of space. I feel the need to reiterate here. Maximum watt output should be held in modest regard at best.

More important is number of 12v rails and the amperage on the 12v rail(s). I try not to go below 12v@20A. These days the higher I can reach above that within a pricerange, the better. The hardware out there now is very demanding on your PSU, not to mention expensive. Buying a good quality PSU is priority one if you want to do your best to insure your investment.

Lastly, all PSUs are allowed a variance of +/-5% on the output of the rails. Its an industry standard. If you're looking at a PSU that claims tighter tolerance, be wary.

My advice is to spend the extra money on a quality PSU. Its the heart of your system. Lower end units can be shaky from the start. As they fail, the output may get all over the place and damage the rest of your system. Certainly, its worth the investment to have piece of mind when diagnosing a problem as well.

Anyone have thoughts on the Corsair CX 400 watt with single rail 30 amp?

Funny, I was just reading about it..

http://www.anandtech.com/casecoolin...aspx?i=3487&p=8

Seems pretty damn good to me!

That is a nifty little PSU...30amps on 12+ rail...nice.

I also like the fact it is made with quality in mind for so little price.