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Power down one core manually? (MBP)

J

jesaja

macrumors member
Original poster
Sep 15, 2003
76
3
Lichtenstein
Hei!

I've heard (where, I don't remember) that you could manually power down one core of the MBP to save power when on the road.
Now that I got my 'Book today (yay - I recieved it as a replacement for a 15"Powerbook!) I've looked for it, then searched google. etc - and nowhere I can find anything how to do it...

So - does it work? And if yes - how?

Thanks a lot, greets,

jojo
 
Well Im sure there is another way, but if you insert the install disk and install the CHUD tools, it will allow you to do this. I just did the custom install and just installed the CHUD tools.

It will add another option in your System preferences called Processor , and you can put an icon in the menu bar. Thats what I did.
 
So what kind of battery life are you getting with one core instead of two? I'd be interested to see your results with one core and two.
 
Koodauw said:
Well Im sure there is another way, but if you insert the install disk and install the CHUD tools, it will allow you to do this. I just did the custom install and just installed the CHUD tools.

It will add another option in your System preferences called Processor , and you can put an icon in the menu bar. Thats what I did.
Click to expand...


Wow - that was a fast answer! Thanx a lot! I'll try that. Didn't hink of installing additional things off the DVDs yet...:rolleyes:

jojo

PS: well - I just have it for 5 hours now, so... *jumping*
 
Koodauw said:
Well Im sure there is another way, but if you insert the install disk and install the CHUD tools, it will allow you to do this. I just did the custom install and just installed the CHUD tools.

It will add another option in your System preferences called Processor , and you can put an icon in the menu bar. Thats what I did.
Click to expand...


Besides battery life, is there any reason you would want to power down one core? I am assuming this would slow all processes?

Just wondering as I am very new to the Core Duo technology (so I should probably read some more before asking these questions:) )
 
What choices are available in Energy Saver>Options on the MBP? (Meaning like, most laptops have Auto, Highest, Reduced.)
 
Aramis said:
Besides battery life, is there any reason you would want to power down one core? I am assuming this would slow all processes?

Just wondering as I am very new to the Core Duo technology (so I should probably read some more before asking these questions:) )
Click to expand...
battery life is pretty much the only reason, except possibly heat issues which sort of goes with battery life.
 
yeah - it works! (Though it was not so easy to find - didn't know these belong to the XCode Tools)
By the way - the monitoring panel is really cool. And the ability to switch off one core with one single click! :D

jojo
 
jesaja said:
you could manually power down one core of the MBP to save power when on the road.
Click to expand...

There are mixed reports about the results of doing this. On PCs, it actually puts extra load on the remaining core such that operations take more than twice as long as with both cores up and thus battery life is negatively impacted. I suggest performing some benchmarks/tests to confirm that battery life is actually extended by powering down one core.
 
I wonder if some folks think that the second core is a second, full-sized processor sitting in their MBP, and that by turning it off they'll save 50% of the processor power. :confused: :eek:
 
aristobrat said:
I wonder if some folks think that the second core is a second, full-sized processor sitting in their MBP, and that by turning it off they'll save 50% of the processor power. :confused: :eek:
Click to expand...

Hey - I'm not stupid. But away from power outlets I'm trying to squeeze out every single minute of my notebook. And so I wanted to try this, too.

And yes - It brings me only about a quarter of an hour, but hey - better than nothing. And 'on the road' I don't need the 'extra power' of the second core, even the first idles ;) around at ~10-20 %...

jojo
 
AlexH said:
So what kind of battery life are you getting with one core instead of two? I'd be interested to see your results with one core and two.
Click to expand...

According to Tom's hardware there's virtually no difference. The processor is not the only piece of hardware that's drawing power..
 
jesaja said:
Hey - I'm not stupid. But away from power outlets I'm trying to squeeze out every single minute of my notebook. And so I wanted to try this, too.
Click to expand...
Fair nuf! Definately didn't mean to imply that you were stupid. Sorry if you took it that way. :)
 
Another reason you might do this is as a developer to see the performance of your app on a slower system.

That said I have also heard that powering down one core has negligible impact on the battery.
 
yippy said:
Another reason you might do this is as a developer to see the performance of your app on a slower system.

That said I have also heard that powering down one core has negligible impact on the battery.
Click to expand...

In my case, this is true... I have seen the battery life remain about the same with one or two cores.
 
I want to disable the second core to reduce the heat that is coming from the ALU! Since I mostly use the laptop for typing, the second core is of little value to me, usually.

Does anyone have any experience with reducing heat by disabling the 2nd core?

And I sure could use a pointer to installing the CHUD and getting the talk about option.

I tried downloading the chud from APPLE and after installing had NO options to disable or anything new in the System preferences.

TIA:D
 
I am using an iMac, but it doesn't to seem to make a difference. Also, It says it is using a Pentium M:confused: ? What the hell. Probably is the closest processor. So thats why the MBP gets so hot...its a pentium:D But the CPU NOISE actually decrease. to MBP users, disable one core.
 
Grokgod said:
Does anyone have any experience with reducing heat by disabling the 2nd core?
Click to expand...
I think I've seen some posts where folks said that running with just 1 core causes that core to run higher/hotter than when the load was distributed over 2 cores.

I'll see if I can find that post...
 
For all of you that think shutting down one of the cores will give you extra battery time, you are WRONG.

One of the best features of the Intel Core Duo chips is that it is ver efficient in conserving power. By shutting down a core, you are taking away that ability from the processor.

When I shut down a core, my battery time remaining instantly drops by about 40 minutes. Obviously, not a smart thing to do.
 
Although it's counterintuitive, using only 1 core will make it run hotter and reduce battery time. I don't know why, but that's what happens. I installed CoreDuoTemp and found that the temp was higher with only one core and you can read here for battery tests that show that it reduces battery time.
 
Just a warning before powering down: You will be degraded to around 1.2 GHz Core Solo instead of 1.83-2.16 GHz Core Duo. This will make it even slower than the Mini... Though it will save a lot of battery.
 
It doesnt save battery time, as a matter of fact it killed my battery time, but it ran cool enough to sit on my lap with nothing underneath.
 
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