Old Pentium III Running 24/7

dylan_m

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I have just got my old Pentium 3 computer set up again, and I was planning on just sitting it in the back of my cupboard with an extension cable running through the door and leaving it on 24/7 to download torrents and contribute to BOINC projects.. And I was wondering if the power usage would build up over time, rendering it expensive to run. It only has a 200W power supply, so I know for a fact that it can't use more than that, but because BOINC tasks keep it very busy at all times, it could easily use, all day long, as many watts as my good computer does at idle.

Here's a few specs for it: 200W PSU and Pentium III (as already mentioned), one 20GB 5400rpm hard drive, 128MB of 357MHz RDRAM (haven't even heard of it before), two optical drives and a floppy drive but I disconnected them from the PSU, and an old graphics card with 8MB of memory and without any kind of cooling design, so I assume it bareley uses anything. And finally it runs Windows XP Professional, but I have stripped it down a lot - no unnessecary processes, startup programs, lowest possible screen resoloution, 16-bit color, and I have activated XP's "Advanced Power Management" feature. By the way, I couldnt find anywhere that says how many watts a P3 processor is.

So yeah any estimates as to how many watts this thing is really using, and how expensive or inexpensive it is to run 24/7, and if you have any recommendations as to how to make it even more power saving, let us know :)

And sorry if this post has a bit too much useless information, I just wanted to include everything I know in the original post.
 

jaguarskx

Titan
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A Pentium 3 CPU generally consumes a max of 10w - 28w of power depending on which one you have.

Your CPU will be idling most of the time, except when it is scanning for viruses. Based on the parts that you have I would guess-timate that your PC will use roughly 60w of power.

If you live in NYC where it costs about $0.19 per KWH, then you are talking about $100 per year in electricity running 24/7. Is it worth building a new computer to reduce power consumption by a little bit? The answer is no.

Edit:

The above is assuming you are using the 1.0GHz Coppermine Pentium 3.

I also forgot to take into consideration the power supply. If you are using an older power supply, chances are it will probably only be about 65% efficient. That means while the PC may actually be using 65w of power, the power supply will be drawing 92w from the outlet. 35w of that 100w is wasted as heat and noise. That would bring up the cost to $153. Also, as a PSU ages it's efficiency drops and becomes more prone to failure like any electronic component.

Many modern PSUs have an 80Plus rating which means they are at least 80% power efficient. If you replace your old PSU with one that has been 80Plus certified, then you will be drawing about 75w from the outlet which means your electricity cost will work out to about $125 per year based on $0.19 per KWH.
 

king smp

Splendid
Moderator
as a guesstimate
I dont think even at 100 percent load that is going to go over 150watts at max
really not running more than a standard flood light

lets say it is 200w just for a round top end number
in 24 hours that is 4800 watts
or 4.8 kilowatts per hour
or times average 10c per KwH about 40.8c a day
or about 148 dollars a year
using US dollars and rates
would be different in other areas
look at your electric bill and see how much they charge by KwH unit

Here this explains it better than me
pasted from here

http://www.sci-ed-ga.org/modules/k6/elec/elec.html

Units Of Electricity Use
The watt (W) is a unit of electrical power, which is the rate at which we use energy. We pay the electric company for the use of energy. A kilowatt (kW) is equal to 1000 watts: kilo is a prefix that means 1000. (Note that k is the normal prefix for kilo, W is the normal abbreviation for Watts and h is the normal abbreviation for hours). A watt-hour (Wh) and a kilowatt-hour (kWh) are units of energy, where 1000 Wh= 1 kWh. The equation relating energy and power is:

Energy = Power x Time

For example, if a 75 W bulb (power) is turned on for 2 hours (time), it will use 150 Wh or 0.15 kWh of energy (energy = power x time).

The cost for each unit of energy we use is measured in cents (c) or dollars ($) per kWh. The typical cost per unit of energy is 10 c/kWh or $0.10/kWh. Using the equation below, we can determine the cost of our energy use:

Cost of energy use = Energy used x Cost per unit of energy:

Using our example above, the cost of using a 75 W bulb for 2 hours is:

Cost of energy use = 0.15 kWh x 10 c/kWh = 1.5 c



so basically at full 200watts max it would cost you @150 USD a year
that is the cost of a 4 person family eating at a restaurant one time

Just FYI
 

jaguarskx

Titan
Moderator
A Pentium 3 CPU generally consumes a max of 10w - 28w of power depending on which one you have.

Your CPU will be idling most of the time, except when it is scanning for viruses. Based on the parts that you have I would guess-timate that your PC will use roughly 60w of power.

If you live in NYC where it costs about $0.19 per KWH, then you are talking about $100 per year in electricity running 24/7. Is it worth building a new computer to reduce power consumption by a little bit? The answer is no.

Edit:

The above is assuming you are using the 1.0GHz Coppermine Pentium 3.

I also forgot to take into consideration the power supply. If you are using an older power supply, chances are it will probably only be about 65% efficient. That means while the PC may actually be using 65w of power, the power supply will be drawing 92w from the outlet. 35w of that 100w is wasted as heat and noise. That would bring up the cost to $153. Also, as a PSU ages it's efficiency drops and becomes more prone to failure like any electronic component.

Many modern PSUs have an 80Plus rating which means they are at least 80% power efficient. If you replace your old PSU with one that has been 80Plus certified, then you will be drawing about 75w from the outlet which means your electricity cost will work out to about $125 per year based on $0.19 per KWH.
 

dylan_m

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Okay, we got the computer around 2002 (to be honest I dont really remember), do you still reakon 65%? And would you say buying a newer, more efficient 200W psu would be worth it? Or even a 150W?

And it's a 733MHz Coppermine.
 

dylan_m

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Well we only used it for about 5 years before buying a new computer.. So it's been lying around for ~4 years without use. And that link you provided was exactly the kind of thing I was looking for, how come you could find it so quickly? Good googling skills there
 

4745454b

Titan
Moderator
I'd like to point out that efficiency that high tends to happen at 50% load or higher. Meaning if you buy a 500W PSU, you'll need to pull 250W to hit 80%+ Seeing as this is a simply low wattage unit, the lower the wattage unit you buy the better. Even the Antec 380W Green would need you to pull around 190ish to hit good numbers. I'd have to look up where it hits 80%.

The other bigger issue you'll have is needing to find one that can power that unit. -5V rails disappeared from modern system, and the +5V might not have enough power. You can't plug a modern PSU into an older system and be positive it will work.
 

king smp

Splendid
Moderator
even though I like keeping old tech going as long as possible (Green thinking)
I would really hesitate to put any money into system
Plus with compatiblity issues like 4745454b talks about
it wouldnt make sense

Just run until it drops
Just make sure it doesn have any crucial files without backup on it

then gives you excuse to pick up little Atom shuttle system cheap :)
 
buying a new pc wouldnt pay for itself in power consumption at all even after a few years.
todays pc's use a lot more power than the old p3's i have (check my info) and it idles at about 50-80 watts (cpu 40 gpu 20ish 3 fans 10 motherboard 5ish) as the gfx turns off after 20 mins the p3 should use less than that even at medium load.
so unless you replaced it with a net book its unlikely you will save anything and more likley you will use more.
my current setup added just over 120 pounds to my bills over the year but its on 16 hours a day 7 days a week at the least. so at an estimate your pc will add about 50 pounds ($75ish) for a year.
 

king smp

Splendid
Moderator
Your actually doing pretty good with that rig

Rignt now I am doing alot of rendering/encoding of video mainly for Youtube and
my daughters new PSP 3000
so I set up a Vegas Pro network render machine to offload the jobs to
a SFF HP Pentium 2.8 HT 3.5gbs ram XP gutted out 40gb HD no Optical drive
audio uninstalled, and going to look into uninstalling USB and other devices
While the Northwood P4 was better than the other ones it still is a little power sucking
brute
In a perfect world I would have a Intel Atom HT as light duty cost efficient renderer
(jobs are not time critical) but the cost compared to nothing since I already had the tower laying around is just not worth it
 

dylan_m

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Thanks for all the input guys :) Really appreciate it

One more question though while we're on the subject of power consumption - can someone do the same calculations for my current 'normal' computer (the one I actually use). The specs are as follows:

AMD Phenom II X4 965 BE
Asus M4A89GTD Pro/USB3
2 x 2GB sticks of DDR3 ram at 1.74volts
Two Samsung Spinpoint 500GB HDD's
Regular DVD/RW Drive
+ a few fans
all running on a Corsair HX-650

This computer is on for a max. of about 15 hours per day. And CPU usage is on 100% alot of the time as im going through a distributed computing phase ;)

I understand if you want me to delete this post and start a new thread. Just let me know
 

king smp

Splendid
Moderator
maybe my numbers were
off
cpu- 125watt i think
2 sticks ram - about 20 watts or so
2 hds - about 50watts
dvdrw spinning about 30watts
few fans about 20 watts
would give you about 275watt as long as you dont have a video card
so I would go with the PSU calculation
now Jag needs to come back with his percentage calculations of efficiency to figure
out actual draw from outlet
I can never figure out the efficiency numbers without a formula to plug into
 

dylan_m

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So go with 275 or 128 watts?

According to thte back of the PSU's box, at 100% load, it's about 84.25% efficient. Don't you then just add the remainder after the efficiency percentage?

So like:

100 - 84.25 = 15.75%
15.75% of 275 = 43.3125
then;
275 + 43.3125

= 318.3125 Watts?

I don't know..
 

king smp

Splendid
Moderator


I am a work from home tech (refurbing towers,virus cleanings,speeding and cleaning up OS,Windoze installs etc)
and make my own schedule

with a high maintenance wife, high maintenance 10yr old daughter,high maintenance 6yrold female AmerBull Staffordshire Terrier
and a grumpy old mother in law this is my time to work uninterrupted

I only sleep about 4-5 hours on a good day LOL
Semi-insomniac also LOL

Pretty cool though
kill time on Toms helping people while doing my thousandth XP Pro install and making money at the same time :)
 

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