Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I'm deciding between a 500 watt PSU and a 600 watt PSU.

I currently have a 460 watt PSU that powers everything but my dvd drive, spare hard drive, and 2 fans.

I've determined 40 watts is enough to power my hard drive (approx 15 watts) and my DVD drive (approx 25 watts). Please correct me if these are bad estimates.

So my question is about case fans. What wattage do they generally use? I can't find this information on newegg hardware specs, or by inspecting the fans themselves. I don't have their boxes anymore.

Also I noticed that these power supplies only increase their amperage for the 5 and 12 volt outputs. Would fans be using only the 3.3 volt output? Would in increase in total wattage for the PSU even matter if i'm only adding fans?

thanks.

share|improve this question
    
great answers, thanks. i'll buy the 600 as it's only 10 dollars more. –  robertpateii Aug 24 '10 at 1:23
add comment

2 Answers

up vote 4 down vote accepted

Case fans usually use 1.8 Watts and are rated at 12 Volts. The molex connector that is usually used on the case fans is 12 Volts by standard (same as your Hard Drive and Optical Drives usually use). Unless you are adding 50 fans I doubt you have to worry about the power supply. You will be fine with the 500 Watt PSU.

share|improve this answer
    
While I agree with this answer, I would like to add that you need to be careful with some very large fans (say bigger than 20cm). I've seen such fans which use as much as 1.5A of current. –  AndrejaKo Aug 23 '10 at 23:19
add comment

Also, be sure of the type of connector ... not all use molex, some use 3-pin to the mobo. But overall, I agree with the 500W PSU. Be sure to plan for the future as well ... any high-end graphics or high-end audio coming? These can draw up 200W peak (and more if you SLI/Crossfire) ... nothing more frustrating than having to keep upgrading the PSU. Good luck!

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.