Energy meter - surprised me

[beanzontoast]

Thinking of replacing one of my 2 main work computers, I thought I would (out of interest) find out how much juice my existing setups use. So I managed to get hold of one of those plug-in energy monitor thingies and did some Sunday afternoon investigations ...

Current system (Dual Core Intel 5300) = 84 Watts plus another 30 for the monitor = 114 Watts

Old system (Athlon 2400+) = 114 Watts plus another 30 Watts for monitor = 144 Watts

Even given that the actual power consumption varies a bit depending on the task being undertaken, on these baseline 'resting' figures the older, less 'powerful' system actually consumes more electricity - and the more powerful (and now I can see, more efficient) one I'm proposing to replace it with uses only 100 Watts!

Also discovered that leaving both systems on standby (instead of switching one off totally when using the other) uses about 8 Watts extra - the equivalent of leaving a light burning all the time.

 

[Yellow Fang]

According to my smart meter, my old PC uses about 45W and the flat screen another 17W. My 12" laptop uses about 10W. More powerful computers, for example, those suitable for running the latest and greatest computer games, use more energy. If all you want to do is surf the net and write a few documents then you can make do with a lower spec computer that doesn't use so much electricity. You can even buy eco-friendly computers in which a major portion of the materials are recycled. That's quite important because the embedded energy in a computer is pretty high. I once heard at a British Computer Society meeting that the manufacture of a PC used as much energy as a small car. I don't believe his, but the embedded energy is still quite high. The process of manufacturing electronic grade silicon for semiconductors is very energy intensive. I don't know exactly what the embedded energy in a PC is. Andrew MacKay in his book, Global Warming without the Hot Air, calculated it, but I can't be arsed to look it up at the moment, but you can access it on line. It is quite probable that the embedded energy in a new PC will far outweigh any electricity savings.

 

[Yellow Fang]

Actually David Mackay reckoned the embedded energy in a new PC is 1800 kWh, which is like 1800 units in your electricity bill. So, your new PC uses 30W less than your old one, so you'd need to use it for 60,000 hours before you make up for its embedded energy. That's about seven years continual use by my reckoning.

http://www.inference.phy.cam.ac.uk/withouthotair/c15/page_89.shtml

 

[Tigerbiten]

My main box uses 700 watts under full load.
My five secondary computers use either 350 or 450 watts full load, it depends on if it has 2 or 3 vid cards in.
I did have a computer that pulled just over 900 watts full load, but that one did have 8 vid cards in.

 

[Davidc]

I now use a laptop for everything, and that takes 75w. if on battery that's equivalent to over 100w (inefficiency in charging it up). If I use the docking station with the backup system attahed thats another 65w, total 140w.

There are 2 laptops in use, the other is older and only takes 42w on mains, equivalent on battery 60w.

The computers are a small but significant part of our electricity bill.

 

[mcshroom]

I just about only use a netbook at home now. That is rated at 19v and 1.85A so It should use just over 35W.

 

[beanzontoast]

My main box uses 700 watts under full load.
My five secondary computers use either 350 or 450 watts full load, it depends on if it has 2 or 3 vid cards in.
I did have a computer that pulled just over 900 watts full load, but that one did have 8 vid cards in.

Wow! Suddenly I wonder what I'm worrying about with my piddling 114 watts!

 

[CopperBrompton]

Powerful 17" laptop: 38W at idle, up to about 77W when busy.

 

[GrasB]

IIRC about ~95 VA @ idle, artificially induced ~310 VA full load (running programmes to give 100% CPU load on each core + fully utilise the GPU at the same time). On top of that an external RAID array putting 5-70VA which is only on when needed, which is whole point of going for an external solution when an internal one would be cheaper & faster.

 

[twowheelsgood]

Both figures are on the "good" side of reasonable actually. Be thankful you aren't using a Pentium IV.

The main factor is modern PCs is actually the quality and therefore efficiency of the power supply. The problem is most of the time it's idling away at a few tens of watts but also you could stick in a high-end graphics card and play a very intensive 3D shooter requiring several hundred watts and a cheap PSU may deliver the power but be very inefficent at lower outputs. I actually tend to use my PCs much less these days as I can manage to do 90% of my computing on my netbook which uses not a lot...

If you want are real criminal waste of power try measuring the output of your set top boxes operating and in standby. Mine using 23W operating and precisely 23W in "standby". The problem is these are actually littel computers and people complain at the boot up time if they are really powered off, so what the manufacturers of the cheapo boxes do is simply blank the picture output in "standby". I even get the audio output still working on my old box. This is a massive problem because of course everyone and his dog has one or two of these often running 24/7...

 

[beanzontoast]

Both figures are on the "good" side of reasonable actually. Be thankful you aren't using a Pentium IV.

The main factor is modern PCs is actually the quality and therefore efficiency of the power supply. The problem is most of the time it's idling away at a few tens of watts but also you could stick in a high-end graphics card and play a very intensive 3D shooter requiring several hundred watts and a cheap PSU may deliver the power but be very inefficent at lower outputs. I actually tend to use my PCs much less these days as I can manage to do 90% of my computing on my netbook which uses not a lot...

If you want are real criminal waste of power try measuring the output of your set top boxes operating and in standby. Mine using 23W operating and precisely 23W in "standby". The problem is these are actually littel computers and people complain at the boot up time if they are really powered off, so what the manufacturers of the cheapo boxes do is simply blank the picture output in "standby". I even get the audio output still working on my old box. This is a massive problem because of course everyone and his dog has one or two of these often running 24/7...

+1 - we have one very cheapo set top box where the sound is constantly present even when the unit is 'turned off'.

I can see me steadily working round the house seeing what's using what (or should that be Watt?) and getting obsessed. Still, daughter did ask to borrow it to try on her computer setup yesterday, so that's progress!

Is there anywhere I can find out in advance how much power the new base unit I'm thinking about will draw? Can't see any details on this in the specs.

 

[twowheelsgood]

Unfortunately, I don't think you can get reasonable numbers simply because peoples usage varies so much. The probable answer will be "no different from any other manufacturers offering of similar spec.".

The only way to make any real difference is probably to "roll your own" and chose a better quality power supply or if you don't need the expandability of a desktop, get a notebook.

 

[Over The Hill]

I have been scratching my head and wondering why my electricity bill is £257 for a quarter.

I have swapped all the bulbs to low energy around the house but in the summer the hot water is heated by electric.

I have two desktops that seem to be on most of the time but i do shut them down at night and also a big flat screen TV and recorder which are both on standby when not actually on. So perhaps that is the answer.

My bill says I used 2214 kwh in 3 months!

in three months there are 2160 hours so that means I am using about 1000w per hour on average! 24kw per day.

Water heating is on for 2 hours per day at 3kw an wifey has the heated towel rail on for 5 hours which is 200w. That then accounts for 7kwh out of the 24 per day.
So ther rest of the house uses 17kw per day...........
TV is 100w when on and 1w on standby (it shuts down) = 1kw per day
DVD is 29w when on 13w on standby and 1w if powersave is on. = 0.5kw per day
Dishwasher is about 700w per cycle at one per day. =0.7kw
Lets say two computers and printer at 300w per hour for 12 hours (one is on all day and eve, 2nd just eve) = 3.6kw
Cooker electric but lets guess 1kw per day max - 1kw
Washing machine is about 1kw per cycle say 3.5 per week = 0.5kw per day
Lighting - Probalby mounts up Say 15 lights on at 10w for 8 hours per day = 1.2 kw per day.
Kettle, hairdryer and odd seldom used items are quite thirsty but are not on for more than a minute or two. Must be less than 1kw per day.
Fridge freezer and second freezer seem to be using 1.7kw per day each so 3.4kw per day

So of my 17kw per day non heating electricity use I can account for only 12.6 kw

What is happening with the remaining 4.4 kw is a mystery to me.

 

[Gerry Attrick]

i have a ups linked to my PC which constantly measures power consumption for the PC itself, router and monitor. It is telling me that I am presently using 140 watts. If you then add say 10 watts for the speakers which are not linked to the ups, I suppose that's not too bad. Can't say that I notices my electricity bill go up after I bought the computer.