How much wattage for a power supply?

JohnJSal

JohnJSal

Active Member
Hi everyone. I'm currently reading about how to build your own PC, but I'm not really seeing any good guidelines for how much wattage you should choose for a power supply. I know it depends on the other components, so I was hoping there was maybe some kind of list or reference I could use that would help me figure out a good wattage range for a power supply based on the components you choose, such as video card, processor, etc.

Thanks,
John
 
Last edited:
As a general rule of thumb, it'd be safer to go with something higher than something lower and burn out your system. There are some pretty affordable 700W power supplies and those work great for almost any system. As a good, general way of telling though, here is a PSU Calculator that works great:

http://www.extreme.outervision.com/psucalculatorlite.jsp

I tend to buy about 100W more in a power supply than this recommends, but that's just me. I like to be on the safe side. Besides, may want to upgrade/update or add components in my system later... Hope this helps!
 
Last edited:
brycematheson712 said:
As a general rule of thumb, it'd be safer to go with something higher than something lower and burn out your system. There are some pretty affordable 700W power supplies and those work great for almost any system. As a good, general way of telling though, here is a PSU Calculator that works great:

http://www.extreme.outervision.com/psucalculatorlite.jsp

I tend to buy about 100W more in a power supply than this recommends, but that's just me. I like to be on the safe side. Besides, may want to upgrade/update or add components in my system later... Hope this helps!
Click to expand...

Thanks very much! There's more stuff there than I understand, but I think it helps with the general idea. Maybe I can post some components later and see what is a recommended power supply amount.
 
ceewi1 said:
Feel free to post. You might find this useful: http://www.computerforum.com/90110-power-recommendations-video-card.html
Click to expand...

Thanks. That was very helpful too. But now I have a follow-up question: I noticed that for the nVidia 8800 GT, which is the one I plan to get, it suggests 400W. So does that mean I need to add 400 to whatever wattage is required by other components, to get a total? Or is it saying that 400 is all I need for the whole system?

Incidentally, I used the PSU calculator in the other post and I also chose the 8800GT and the total wattage suggested was less than 300. :confused:
 
No, ceewi1's write up suggests the power supply for a typical system but his second paragraph states that if you have any other power hungry modules then go a little higher.
 
TFT said:
No, ceewi1's write up suggests the power supply for a typical system but his second paragraph states that if you have any other power hungry modules then go a little higher.
Click to expand...

So then it's safe to base your power supply needs on the graphics card alone? How do you know when you need to start looking at other components as well? Here's what I know I want for sure:

Intel Core 2 Duo E6850 (3ghz)
nVidia GeForce 8800GT (512mb)
2 or 3gb DDR2 RAM
320gb HD (maybe 500gb)
DVD+-R drive

I would imagine it's just the first two that really have an impact on power consumption, and since the Core 2 runs pretty efficiently, maybe the suggestion of 400 is all I would need.

The Dell XPS 420, for example, comes with either 375W or 425W, depending on the graphics card you choose. So I guess 425W would be enough then.
 
JohnJSal said:
So then it's safe to base your power supply needs on the graphics card alone? How do you know when you need to start looking at other components as well? Here's what I know I want for sure:

Intel Core 2 Duo E6850 (3ghz)
nVidia GeForce 8800GT (512mb)
2 or 3gb DDR2 RAM
320gb HD (maybe 500gb)
DVD+-R drive

I would imagine it's just the first two that really have an impact on power consumption, and since the Core 2 runs pretty efficiently, maybe the suggestion of 400 is all I would need.

The Dell XPS 420, for example, comes with either 375W or 425W, depending on the graphics card you choose. So I guess 425W would be enough then.
Click to expand...
A 425W power supply is not enough for that system. Personally I wouldn't go any lower then 600W, and thats assuming you choose a high end model with a high amperage no the +12V rail(s), and high efficiency.
 
[-0MEGA-];831605 said:
A 425W power supply is not enough for that system. Personally I wouldn't go any lower then 600W, and thats assuming you choose a high end model with a high amperage no the +12V rail(s), and high efficiency.
Click to expand...

Well, it does seem rather low, but what would happen if you used it? It seems weird that they wouldn't offer something better if the system really required it. The XPS 720, on the other hand, comes with a 750W (or 1KW) power supply.
 
You must log in or register to reply here.
Back
Top