Sign in with
Sign up | Sign in
Your question

Wattage

Last response: in Components
Share
December 3, 2012 7:59:37 PM

Hello all,

I'm planning on doing a completely new build soon and today got my hands on a wattmeter, a nifty little device whereby it shows the instantaneous wattage going from the wall socket to whatever is plugged into it. So I decided to see just how much wattage my computer was using (i'd always been curious).

Now, it is to my understanding that a power supply only draws the amount of wattage the computer needs at any given time.

Here are my systems specs, as you can see, getting on a bit nowadays:

Intel Core 2 Duo E6700 (2.6GHz)
GeForce GTX 280
4 sticks of 1GB ram
2 traditional SATA hard drives

I have a 800W PSU in this thing.

Upon booting to the desktop the wattmeter recorded that I was pulling 130W. I decided to run Future Mark Vantage to strain the system (and it did), yet the wattmeter recorded that I was only pulling about 300W under load.

Surely something gives, I knew at the time I built the system that 800W was a bit of an oversight, but back then the GTX 280 was the most powerful card out and I wanted to play it safe.

But given that I'm only pulling less than half that wattage, is it true I could have well bought say a 400W PSU?



Thank you for your time!

More about : wattage

a c 288 ) Power supply
December 3, 2012 8:37:18 PM

Xylaquin said:
Hello all,

I'm planning on doing a completely new build soon and today got my hands on a wattmeter, a nifty little device whereby it shows the instantaneous wattage going from the wall socket to whatever is plugged into it. So I decided to see just how much wattage my computer was using (i'd always been curious).

Now, it is to my understanding that a power supply only draws the amount of wattage the computer needs at any given time.

Here are my systems specs, as you can see, getting on a bit nowadays:

Intel Core 2 Duo E6700 (2.6GHz)
GeForce GTX 280
4 sticks of 1GB ram
2 traditional SATA hard drives

I have a 800W PSU in this thing.

Upon booting to the desktop the wattmeter recorded that I was pulling 130W. I decided to run Future Mark Vantage to strain the system (and it did), yet the wattmeter recorded that I was only pulling about 300W under load.

Surely something gives, I knew at the time I built the system that 800W was a bit of an oversight, but back then the GTX 280 was the most powerful card out and I wanted to play it safe.

But given that I'm only pulling less than half that wattage, is it true I could have well bought say a 400W PSU?



Thank you for your time!


Hi - well you don't need 800w for sure. With that card tho 400w is cutting it too close, NVidia suggests 550w

and that is prob just about right.

Tom

a b ) Power supply
December 3, 2012 8:39:36 PM

Hi :) 

People (and websites) ALWAYS overestimate the wattage they need.....as you just proved...

You are fine...

All the best Brett :) 
Related resources
a c 130 ) Power supply
December 3, 2012 8:59:30 PM

While you could've bought a 400W PSU and it probably would've worked - PSU's are somewhat unregulated on how they can advertise/describe their product (80+ certification helps us there a little). A PSU sold as a 400W unit may be describing it's max output and not continuous output (max output can be for as short as .1s). It's continuous output may be 75% of that (less possibly). Hardware manufacturers are aware of these 'inconsistancies' and adjust recommendations for power with them in mind.
I would expect to have no problem running an X-fire setup on my 650W even though the recommendation for my card is 750W minimum for X-fire. That is where researching your PSU choice can pay dividends in the end. Will you save money by all the research? Not right away since many "high power", low quality PSU's cost less than their lower wattage, higher quality brethren but you can expect better performance from your computer for longer with a quality PSU (so it does pay off, IMO).
My $0.02 worth
a b ) Power supply
December 3, 2012 9:00:37 PM

A high quality 450w probably would have sufficed, for a while at least.

Over time PSUs perform worse, so a device with a lower wattage starting would sooner hit the point of complete inability to perform than one with a higher starting wattage, theoretically anyway.

Anyway, I would have probably went for something 450w - 550w.

In the future, if you just get a high quality PSU of whatever wattage the video card maker says, that is probably good enough. You don't need to be conservative even from there.

The manufacturer's stated figure assumes you are going to buy a complete POS of that wattage, as long as you buy a good one of that wattage that is all of the conservativeness you need.
December 3, 2012 10:36:12 PM

thanks for your advice guys.

Another reason I'm asking is I'm considering a fanless PSU to power a GTX 680, but the highest wattage on one of these (I've found so far) is 520W.... which may be cutting it a little tight judging by what you guys have advised.
!