how much current will a cpu draw

[brian8]

hi all,

Has anyone here measured the cpu current draw? I just measured mine and it said 0.4A (CPU only) but I am not sure if it is correct. Here are my specs

Dual core 2.6GHz, 2GB RAM, Windows XP, no video card

Thanks

 

[betwixt]

It depends very much on what the CPU is doing. 0.4A seems very low though, some CPU take 20 Amps or more.

Brian.

 

[tpetar]

CPU current depends from CPU type, model and generation.

There is mobile type CPU, they use less energies and current, because this devices such as laptops use batteries.

But desktop CPUs have power consuption for example from 50W and over 100W. Current can be over 30A. You can see lots of strong SMD MOSFet-s arround CPU socket.


Also, there is option for reducing CPU current, when CPU idling, this reduce heat and power consuption. For older PCs they can use software called "CPU Idle Extreme" for the same purpose.

 

[mtwieg]

There's no way 0.4A is a realistic number, unless the thing is on standby/sleep. Modern CPUs draw 10A or more while operating, and much more when under heavy load.

How did you do your measurement?

 

[tpetar]

Brian8 can you describe how you measure current of working CPU on motherboard ?

Did you measure on HV side current change or power change ? or you monitor current on PSU wide connector 3,3V ,...


Cheap (less then ~10eur) unimer instruments, often have terrible current shunt, and make high voltage/current drop in circuit, which give wrong picture of voltage/current in circuit. Also accuracy of this cheap instruments are ok only on paper specification, in real life this is very very sad, and may lead to wrong conclusion and bad measuring datas.

For measuring currents on wide PSU connector of particular wire-pin use Hall sensor type for measuring, with ferite opening clothespin.

**broken link removed**


I suggest you to use CPU-Z software to get detailed informations about your CPU, then try to get CPU datasheet from manufacturer web site.

http://www.cpuid.com/softwares/cpu-z.html

When you get thise manufacturer datas about your CPU then you can measure and compare this data with data in specification given by manufacturer.

You can see some other examples of measuring current with Allegro ACS serie Hall sensor here:
**broken link removed**

 

[FvM]

ATX boards supply the CPU DC/DC converter through a dedicated 12C 4-pin connector. Do your measurements refer to the 12V node current?

 

[brian8]

hey guys thank you all for replying !!!!!!!!!!!!!

I am very sorry guys, when I meant CPU current draw I was talking about current drawn from the wall. I was referring to AC current needed to power the whole computer (motherboard, processor, hard disk etc).

The standard supply in our country is 230V/50Hz with a maximum of 30A per house. I measured current using a multimeter (AC amp scale) connected in series with the computer and the wall.

Thank you very much for your informative answers !!!!!!!!!!!!!!!