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Stupid question but...

Community Veteran
Posts: 14,345
Thanks: 685
Fixes: 10
Registered: 01-08-2007

Stupid question but...

Does a CPU use more resources the hotter it gets?
I only ask because I have one machine with a massive great heatsink on it and the biggest noisiest fan you'd never want and copying 4GB files it's on average using 35-40% of its CPU. It has 512MB SDRam (don't laugh yes its old) and a 1.46GHz AMD Athlon. CPU temperature is in its low 30s.
The machine its copying to has a smaller heatsink thats got a nice small quiet fan attached (well noisy but quieter than the above mentioned machine), uses 55-60% of its CPU, has 768MB DDR ram (fairly modern) and a slightly faster 1.5GHz AMD Athlon. CPU temperature is roughly 45-50.
Is the heatsinks effeciency at heat dissipation what causes the CPU usage to go up or down?
I need a new signature... i'm bored of the old one!
4 REPLIES
paulby
Grafter
Posts: 1,619
Registered: 26-07-2007

Re: Stupid question but...

No, it's quite the opposite!
The more you ask the CPU to do, the hotter it will get as it's having to work harder (put simply).  It will use less power (and hence dissipate less heat) when it's idle and will consume more power (and dissipate moe heat) if you ask it to do something that requires a lot of CPU usage.
More CPU usage = more heat dissipated (not the other way round!)
A more efficient heatsink and fan will just keep the CPU cooler under the same conditions as it will carry the heat generated away more quickly.
Community Veteran
Posts: 14,345
Thanks: 685
Fixes: 10
Registered: 01-08-2007

Re: Stupid question but...

Thats what I thought initially - I just had to ask.
Ok, so why are all of my more powerful machines using more CPU than a less powerful machine?
The only difference is the less powerful has a bigger heatsink and almost industrial fan. Oh and it uses SDRam.
I need a new signature... i'm bored of the old one!
paulby
Grafter
Posts: 1,619
Registered: 26-07-2007

Re: Stupid question but...

It depends on a few things - what processes are running in the background, clock speed, amount of memory installed, processor architecture, amount of CPU cache, etc.
There is no definitive answer!
Community Veteran
Posts: 14,345
Thanks: 685
Fixes: 10
Registered: 01-08-2007

Re: Stupid question but...

Thing is as I've just said, the machine using more CPU has far better hardware. For a start it has MORE memory and it is DDR.
The lower spec system uses SDRam and has less and it uses less CPU. Now why isn't it theother way around as it should be?
Plus the higher spec system using more CPU is a fresh system which was only put into service days ago. The older lower spec system has been running on the same OS for the last few months.
So where is the logic in upgrading?
I need a new signature... i'm bored of the old one!