Is it true that a hot CPU uses more Juice than a cool CPU?

Big.Wayne

Big.Wayne

Big.Wayne

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Greetings my Technological Brethren, :cool:

I been meaning to ask this question for a while. I have read a few bits here and there on the web that a CPU draws more power when it is running hot?

Is this true?

Can anyone explain this to a non-engineer? :o

I know that no hardware is identical but for arguements sake lets say you have two identical machines (same specs, same MHz etc) however one is well cooled and the other is running a little toasty. . . . Why would the CPU in the hot machine need more juice?

I am just curious to find out if running a hot CPU will mean higher electricity bills from some 24/7 machines.

Thanks in advance! :)
 
Thanks for replies :)

I am of course aware that regarding overclocking, a cooler chip is desirable but I am thinking of this subject from another angle which is lower running costs and being ECO-Friendly

I have always thought of premium 3rd Party cooling as a way of achieving big overclocks but never as a way of running a chip at stock (ish) speeds with very little voltage.

i.e People who don't want to overclock would still benefit from paying for premium cooling and 'undervolting' their now super-cool chips.

While overclocks of 4GHz to 5GHz and amazing benchmark results attract a lot of attention in our geeky-world, it seems running costs and general eco-concerns get shoved way down the list of things people find interesting.

I have noticed more and more advertising is now being aimed at so called GREEN features and slowly I am starting to pay more attention to it.

I did really want to get a Q6600 G0 and overclock it to at least 3600MHz but having seen this chart I changed my mind! :eek:

core2powerxq1.jpg


My new subject of interest for 2008 is getting as much performance out of computers while at the same time reducing my electricity costs, seems like my experience of overclocking and cooling could be used to help me achieve my aims here, I don't expect that many people will be interested but hopefully one or two folks will be?
 
Justintime said:
Problem: Cost of 3rd party and more effecient cooling may override whatever you save on electricity, possibly even cost more per annum
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Indeed, not sure about that but will let you know, would still be using less power though.

Justintime said:
I'd undervolt with the stock cooler and most cpus will run stock speed at drastically reduced vcore.
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That's what I have been doing with suprisingly good results however even when the stock cooler is put on reduced rpms (ASUS Q-Fan etc) its still produces some noise, I am thinking of running a premium cooler passive (silent low voltage system), then at the end of the year I can put all the money I saved towards. . . . . a pint of milk or something useful! :D
 
Jokester said:
Take a CPU running at 1V, with 100A going through it, generating 100W (meaning our chip has an effective resistance of 0.01R)
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Thanks for the effort Jokester, it obvious from your post that there is a huge difference in our levels of engineering knowledge! :o

I'm happy to take what you say as gospel as I have no way of understanding any of this! :D

I don't know the difference between a volt, an amp or indeed a watt, or what their relationship to each other is, also TDP, resistance etc

I wonder, could you put that brain of yours to work for me and do some calculations on the following. . .

Take an E6300 chip running in two scenarios

#1 running at stock 1.86GHz, 1.28vCore actual, load temp of 45°C

#2 running at 1.86GHz, 1.06vCore actual, load temp of 32°C

How much less power (watts?) would example #2 use over a 24 hour period?

thanks for the loan of the grey matter! :)
 
sablabra said:
Overall I only suspect your computer will draw a few percent less power in your scenario.
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Thanks sablabra,

yeah I will have to get one of those power block things and see, even though it measures the whole system load I should be able to work out how many extra watts are being used between the two difference scenarios.

If that screenshot above is accurate, I was quite suprised to realise that a stock E8400 when loaded will use almost half as much electricity as an overclock Q6600 at full load, thats like two 100w lightbulbs extra running 24/7, day in day out.

I will source me a power block thingie and check for myself, off the top of my head I will aim for a power useage of 150w when the system is idling and 200w under full load, once that is achieved I will start to work out ways to shave it down further.

Would be a cool thing to build powerful computers that can run all tasks fast and smoothly while not burning more than 100w at full load.

thanks for all the helpful replies peeps, good luck with your 5GHz overclocks! :D
 
Hi again,

I'm trying to get one of those things that fit inbetween the computer and the mains and show me how much power is being used but I have no idea what this device is called? :o

Can anyone tell me what I should be looking for please! :D
 
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