power usage

[chrcoluk]

I am currently checking why I am using so much electric, I have read articles that state a modern pc uses little power now days as cpu's are efficient etc.

I just tested my laptop tho and the results are alarming, I would find it very hard to believe my pc uses less power than my laptop.

first here is a quote from a guy on another site about his pc power usage (lower than my laptop).

600W PSU
Pentium D 925 3.0 (i think with a TDP of 120W)
XFX 8800GS
Intel DQ965GBF
HDD Sata II SP250 Samsung
(2 X 1)GB Kingston DDR2 667

While booting the PC consumed 120W
When it was in idle 108W
Playing Crysis 208W
Suspended 4W
When it was off 3W**

and here is my laptop power usage

10 watts plugged in idle
130 watts plugged in charging
165 watts turned on idle screen off
185 watts turned on idle screen dimmed
200 watts turned on idle screen normal
300-320 watts turned on under load

I keep my pc on 24/7 for various reasons.

lazyness
i dont like power cycling hardware as I believe it accelerates failures especially in hdd's and fans also my last psu died on a power cycle granted it was getting old but it still was a power cycle that killed it.
ambient noise helps me sleep
saves me time when sitting down to start using it as everythng is how I left it (I realise sleep/hibernate handles this also tho, although that would kill network connections such as idle ssh sessions).

however my electric is expensive and I will probably have to change my habits but first I am determining if my pc is really using so much.

has anyone here used a watt meter on their laptops or pc's?

 

[Tsumi]

Without knowing the specs of your laptop, it's impossible to determine whether the power draw is normal or not. The guy's desktop doesn't take the screen into account, while the laptop has a screen to power. Additionally, the laptop power bricks are generally less efficient than computer power supplies.

 

[chrcoluk]

165 watts with screen off.

spec is celeron m575 - ich8m
3 gig ram
single hdd

 

[chrcoluk]

ok here is the results, I am confused.

Basically when in the bios 400 watts.
desktop 410 watts idle
3d app running stressing gpu 410watts

on post power goes down to about 40 watts
during bootup 380 watts

so it seems as if its taking full juice all the time even when idle, I can confirm my gpu downclocks on idle and my cpu does as well. But no change in power usage.

 

[Dangman]

Yeah whatever watt meter device you're using is pretty much inaccurate. Even old laptops didn't use anywhere near that much power.

 

[chrcoluk]

I messed up sorry.

It was the lcd I had plugged in and due to the power socket been hard to see I missed the decimal place.

so the lcd is using 41 watts 41.0.

now with the correct plug in here is what I have collected, I messed with some cpu options to get some data on c-states and stuff also.

With my normal config. c-states and c1e are off.

6 watts powered off
160 watts post/bios
145 watts idle eist off (full clocks locked)
128 watts idle eist on (reduced clocks)
210 watts 3d benchmark running

thats quite good so my pc uses less electric than my laptop, surprised me a lot.

here is some other figures.

with c-states enabled idle goes down to 122 watts so c-states saves 6 watts, far less than what eist saves.

with c1e enabled idle is same as eist, but voltage fluctates a lot less when load is sporadic so c1e has a more agressive power saving than eist which is what I had observed before but now confirmed with watt meter.

bios option called "enable full power mode" I have had this enabled 24/7, other option is auto. When I selected auto was zero power saving I observed.

bios option called "acpi 2.0", no affect on power.

windows option pci express low power mode, zero affect on power.

 

[chrcoluk]

Yeah whatever watt meter device you're using is pretty much inaccurate. Even old laptops didn't use anywhere near that much power.

I will remeasure the laptop is possible I made the decimal place error on that also.

 

[runs2far]

That power reading is way off.

Look at the power brick, it will be rated for a certain DC power output, something like 19V 4A. You can use those two numbers to calculate the maximum rated power consumption possible on that power brick, as this will be 19*4 = 76 Watts

The CPU in that system uses 31 Watts max.
If you are on integrated graphics, normal with a Celeron, you can add 5-10 Watts max. for the IGP and other peripherals.
Finally the LCD screen and backlight uses less than 10 Watts.

The above numbers are estimates and on the high side of what you will ever see in that laptop.

It is _not_ possible to cool 210 Watts of heat in a regular laptop chassis and that laptop will have to feature a high end GPU to reach that number.

EDIT:
Forgot these.

HDD ~3 Watts
ODD ~5 Watts
WIFI ~3 Watts

Those three numbers are maximum, as in ripping a CD to the HDD and reading a file of the HDD and transmitting it over WIFI while copying a file on the HDD.
Under normal operation the ODD will be off, the WIFI at 1 Watt and the HDD will jump between 0.5 and 3 Watt as it will idle or read a little data.

 

[chrcoluk]

I will do this tommorow as too tired now, but its very likely I simply missed the . so 300 means 30 and so on.

The laptop now has had a swap of cpu to a core2duo t5750, which as I udnerstand it should have lower idle power draw but slightly higher full load draw.

In any case my pc is using less than I was concerned, as my power bill suggested it must be using 300+ watts on idle which I am relieved it isnt.

 

[chrcoluk]

17 watts on idle
13.5 watts on idle screen off
38.5 under load

for laptop so yes I got digit wrong. looks like this new cpu saving power over the celeron idle.

 

[runs2far]

17 watts on idle
13.5 watts on idle screen off
38.5 under load

for laptop so yes I got digit wrong. looks like this new cpu saving power over the celeron idle.

OK

If you are concerned over your electric bill, try looking at stuff that is always on, refrigerator, Freezer, radio/TV, network etc.

You will probably get a surprise when you add them up.

 

[Tsumi]

OK

If you are concerned over your electric bill, try looking at stuff that is always on, refrigerator, Freezer, radio/TV, network etc.

You will probably get a surprise when you add them up.

Indeed. Using a microwave for 5 minutes will probably use more power than your laptop uses in 3+ hours.

 

[evilsofa]

What you can also do is find out where the electric meter for your house/apartment/foxhole/whatever is and note how fast the value is going up. Then go to your fuse box and turn off all of the circuits (taking care to turn things off beforehand, don't cut off Granny's life support, don't piss off the neighbors if you're in a shared building, etc). The electric meter should stop entirely at this point; if it doesn't, have a chat with your electric company. Now turn on each circuit by itself and see how fast it makes the electric meter go up to see which ones use a lot.

 

[chrcoluk]

my electric bill is actually lower than average but just seemed high compared to a few people I know.

However after getting these readings, the usage is about right.

I average 9-10 units usage a day.

What I have always on is.

PC
Fridge/freezer
Broadband/network equipment which for me is actually a modem + 3 routers. (1 router uk samknows monitoring, 2nd broadband router, 3rd router used as a switch for my gigabit lan).
Laptop recently has also been on 24/7 but isnt always on all year round.
PC monitor is on 16 or so hours a day.

my tv is off almost all the time as I watch tv on my pc.