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Huge success undervolting the Air!

Parallels or VMWare Fusion, running either of those and booting up an OS will cause the fans to spin up. Undervolting just basically keeps the temps low enough that the fans might not be as loud as stock voltages. Nothing more. Any CPU intensive programs will cause the CPU to heat up rapidly, you can't change that, unless all you do is just playing music.
 
Particular said:
unfortunately no this program does little for fan noise
Click to expand...

does little, but it does do something.

seen here:

Picture2-6.jpg


I've been running iSquint for the past 15 minutes and the temps only hovered at 75-77 deg C, fan speed only at 4k+ and not going any higher. Hardly noticible fan noise, infact, my external hard drive is louder then the fan.
 
ayeying said:
does little, but it does do something.

seen here:

Picture2-6.jpg


I've been running iSquint for the past 15 minutes and the temps only hovered at 75-77 deg C, fan speed only at 4k+ and not going any higher. Hardly noticible fan noise, infact, my external hard drive is louder then the fan.
Click to expand...

I don't get noise with parallels, it runs well. But i'm running cool book.
 
This may have already been answered but I skimmed through the 6 pages and didn't see an answer....

Question is.... does coolbook app need to run in order to have the setting applied? also, is there a way to only show the menu bar stats without having the dock icon and the application window on the screen... I know its not a big deal to minimize but, its just one of those things that would make my life a whole lot better lol..

thanks

stakis
 
darwiniandude said:
I don't get noise with parallels, it runs well. But i'm running cool book.
Click to expand...

My point of view: Fan rpm and noise is very much depending on how long you are demanding heavy load from your cpu, and if you start the load on cold or on an already warm state. And: The fan never reacts immediately, it more stays calm as long as possible, and only speeds up when the thermal sensors will tell him to do.

1) I've played with CoolBook for a few days and can tell you that I had 4 situations of freezing my MBA which I never had before.:rolleyes:
2) Further I can confirm that watching this flash content of youtube for more than just a few minutes on the MBA (1.6/80) will still kick your fan to spin at higher rpm. With and without CoolBook. I’ve played with settings going from 9.0 V up to the standard voltages.:rolleyes:

For 1) I still might have to find the optimal settings for my processor. For the time being I have now deactivated CoolBook. But I am running the app just for observation of current frequency, voltage and cpu temp in the menu bar. And guess what: most of the time my MBA still runs at 800MHz and 9.0V based on its very own SMC controls! :eek:

So I rather believe that CoolBook mainly targets users which are really heavily loading their MBA with gaming, graphics whatsoever. Before having read about those so called core shut downs in this forum I even didn’t know about them! Don’t blame me for that, but I think that you might benefit not too much using CoolBook as long as you don’t belong to those heavy users. I don’t.

I might get a bit more experienced in this and change my mind again, but for the moment that’s just my two cents. And of course only concerns using CoolBook on my MBA which is an 1.6/80.

Rds
 
Thomi said:
2) Further I can confirm that watching this flash content of youtube for more than just a few minutes on the MBA (1.6/80) will still kick your fan to spin at higher rpm. With and without CoolBook. I’ve played with settings going from 9.0 V up to the standard voltages.:rolleyes:
Click to expand...

Youtube does kick in the fans, but not as high anymore. I only got about 3600rpm max after 2 hours of surfing and watching youtube vids.
 
I must say, that I have now had it freeze twice. No biggy, i've seen that in the past with overclocking (meaning i was running a pc at above recommended speeds) and in that situation, more voltage helps. Mine was set at:
800 0.9
1200 0.9
1600 0.9

I've now made it
800 0.9
1200 0.9125
1600 0.9250
and added a 600 0.9 for battery use.

So far, so good... i did this mid yesterday, no more freezes so far. I'll give it a week and see what happens :)

But yes, you're quite right; if you've not stressing the cpu, coolbook won't do much, but it does for me atleast mean that when i do encode some video (making a youtube flv into an h264 for the iphone for example) or playing a bit of warblade, or just watching a movie while time machine is wirelessly backing up my air.... with coolbook all this is possible with minimal fan noise and deffinately less heat.

You said the app doesn't work for you, and while i don't doubt you, are you sure you've set it up correctly? The demo does nothing, and the full version by default echos the stock setttings. It has a confusing interface, you have to read the instructions. Definitely an app that would benefit from a GUI rewrite, and sitting down with some humans and observing how they failed to interact with the software.
 
ayeying said:
Youtube does kick in the fans, but not as high anymore. I only got about 3600rpm max after 2 hours of surfing and watching youtube vids.
Click to expand...

In my MBA Youtube kicks the fan up to max (6000 rpm) after about 15 minutes of constant watching a long clip (I am not talking of surfing over Youtube and watching different clips whereas the cpu can cool down between each of them..) and then comes back to about 4000 rpm as a result of the initial 6000 rpm kick. But it will keep on waving between +-3600rpm and +-5500 rpm. All this with and without using Coolbook with even lover Voltage settings than the thread starter had.

Using CoolBook with Youtube will let the CPU run at 800MHz and 0.9 Voltage at most of the time and sometimes for very short sequences jump to 1200MHz and 0.9somewhat Voltage. Not using Coolbook will do exactly the same with my MBA! I would have to run CoolBook with massive lower settings in the lower speed range. Perhaps 0.8 Volts for both 800 and 1200MHz? :eek:
 
darwiniandude said:
You said the app doesn't work for you, and while i don't doubt you, are you sure you've set it up correctly? The demo does nothing, and the full version by default echos the stock setttings. It has a confusing interface, you have to read the instructions. Definitely an app that would benefit from a GUI rewrite, and sitting down with some humans and observing how they failed to interact with the software.
Click to expand...

darwiniandude if you meant me, I think I managed to use the app to freeze my MBA :D. But you are right, the GUI could be more user friendly.
 
faster for the same power consumption?

My settings are as follows for my MBA

800 MHz 0.9000 V
1200 MHz 0.9000 V
1400 MHz 0.9000 V
1600 MHz 0.9125 V

I am under the impression that the CPU power consumption is only defined by the voltage and NOT the frequency.

In other words, am I better off deleting the 800 and 1200 MHz lines in the settings, forcing my MBA to run at minimum 1400 MHz (since power-wise, it's the same as the lower speeds)?
 
In my limited testing, high mhz do cause more power consumption, less battery life. When sitting idle at 1600mhz, battery life shows less than sitting idle at 600mhz.
 
silverblack said:
My settings are as follows for my MBA

800 MHz 0.9000 V
1200 MHz 0.9000 V
1400 MHz 0.9000 V
1600 MHz 0.9125 V

I am under the impression that the CPU power consumption is only defined by the voltage and NOT the frequency.

In other words, am I better off deleting the 800 and 1200 MHz lines in the settings, forcing my MBA to run at minimum 1400 MHz (since power-wise, it's the same as the lower speeds)?
Click to expand...

The amount of power used in a logic circuit can be calculated by the equation:

P=cv^2f

where c is capacitance (set by the device we can't change it)
v is voltage
and f is frequency.

Since the voltage term is squared, you will see a much more dramatic effect on power by reducing the voltage than you will by changing the frequency, but frequency is still part of the equation. You will see a linear change in power based on change in frequency.

This only covers the part of the power created by dynamic load switching. There is also a component of power that is static. The static power is the amount the circuit draws just because power has been applied. Static power will only change with the voltage, not with the frequency. This just adds to the gains seen by lowering the voltage. Even if the frequency is zero, you will still draw the static power.

Long story short, you will not see gains as big from lowering frequency, but there is still a difference in power consumption. The slower you can run, the better. I would not run the frequency too low, though. There are some chips that require certain clock frequencies in order to operate properly. I personally have not checked the data sheets of the chips in the Air, but some PLLs can actually be physically damaged if the clock speeds are too low.

-Matt
 
OK, got it installed and tweaked...

I am embarrassed to say that I went too low right off the bat and ended up in a kernel panic reboot loop. (Meanwhile, I have been OC'ing PC's for many many years so I should know better.) Anyway, I rebooted to safe mode (hold down shift after the start noise until the spinning gear starts) and reset coolbook to defaults.

As of now, I can run it totally stable at 1800 at .975 volts... I may actually be able to go lower, but I will try some more tomorrow.

I can finally play WOW and not have it turn off my CPU's every 3 minutes. Also, the temp never went above 78C after 20 minutes when previously it hit 84 and started to shutdown my cores... causing major slowdowns and stuttters.

Everything else runs about the same... maybe a bit cooler.

So far, the tweaker in me loves this little app.
 
Glad you saw the same results. This $10 is what has enabled me to hang on to the air i love so much. I just couldn't live with a computer that i couldn't convert video files on occasionally. I don't care how slow it might be but it needs to be able to sit there and crunch through the frames. and now it can.
 
Beliyaal said:
You can find the smc command line tool in the smcFanControl app. Just be aware that it might not be advisable to change the maximum speed of the fan. I'm conflicted if an app should be created that makes this easier to achieve. It might cause apple to remove the possibility to set the maximum fan speed in future updates to the SMC firmware.
Click to expand...

Hi, thanks for the tip. I've tried poking around the app itself and I cannot find, at all, how to access the command line. I've googled searched as well but have no luck.

Is it just regular terminal? And I simply plug in the command you posted earlier (smc -k F0Mx -w 3e80)?

Further, what is the command to allow the max back to 6200rpm?

Thanks :)
 
pgharavi said:
Hi, thanks for the tip. I've tried poking around the app itself and I cannot find, at all, how to access the command line. I've googled searched as well but have no luck.

Is it just regular terminal? And I simply plug in the command you posted earlier (smc -k F0Mx -w 3e80)?

Further, what is the command to allow the max back to 6200rpm?

Thanks :)
Click to expand...

Basically in terminal:
Code: 
cd /Applications/smcFanControl.app/Contents/Resources
smc -k F0Mx -r
smc -k F0Mx -w 3e80

Or you might need to do this:
Code: 
cd /Applications/smcFanControl.app/Contents/Resources
sudo smc -k F0Mx -r
sudo smc -k F0Mx -w 3e80

the smc -k F0Mx -r will give you the default value for 6200 rpm.
 
I have read all the post in this thread and am wondering if the 10 bucks is worth it or not. I don't have any problems with my MBA and it is a 1.8/80. I do notice a ramp in the fans when viewing YouTube and a few other times but I hover around 48 degrees and 2490 RPM on my fans.

For 10 bucks it might not hurt. Has anyone that wasn't experiencing thermal shut downs or high temps and loud fans applied this app to their MBA? and if so, has it helped out any or is it more for those who have experienced the shutdowns and high temps.
 
dthree36 said:
I have read all the post in this thread and am wondering if the 10 bucks is worth it or not. I don't have any problems with my MBA and it is a 1.8/80. I do notice a ramp in the fans when viewing YouTube and a few other times but I hover around 48 degrees and 2490 RPM on my fans.

For 10 bucks it might not hurt. Has anyone that wasn't experiencing thermal shut downs or high temps and loud fans applied this app to their MBA? and if so, has it helped out any or is it more for those who have experienced the shutdowns and high temps.
Click to expand...

I didn't espirienced core shutdowns on my week 05 MBA. But for $10 I decided to give the coolbook thing a try. I mean if I can run the MBA at a lower voltage whilst at the same clock speed, why not?

After applying coolbook, and running all the speeds at 0.900V, the expirience was good personally for me. Since I didn't really have core shutdowns before this, this wasn't a concern. However, the average running temp of the MBA decreased. With this decrease the fans kicked in later and less often. Now they only kick at their max rpm after a longer period of sustained heavy CPU load.

So I say it is worth it.
 
Ok, I am sold. I purchased it and set my settings to .9v for everything except 1.8ghz and my temp didn't break 57 when stremaing you tube where before it went to 80 degrees c and my fans went cranking.

Stand alone temp is even cooler than before. Maybe it is not accurate because the temp in the program is 3 degrees different than in istat but ti does maintain a steady temp when pushed.
 
i just purchased this product, but i cant seem to get it to work.

i have the same settings as the threadstarter but somehow the settings dont work.

when i load my cpu, the default voltages are still being used, not the tweaked ones.

can anyone help?
 
what's up with this limited license purchase...

we should be able to reset activation as much as we want to..

i mean i reinstall os x every 6 months or so..

according to the license i can only reset it once...i have to shell out $10 every year or what..

otherwise i'd buy this little program in a heart bit...
 
So what the heck I decided to give the application a go - even though I haven't really had any core problems or temperature problems with my MBA.

(battery charge times not withstanding)

But my oh my I am impressed. This has got my MBA down to around 30c for surfing the web / checking email.

Under full load I'm only at 62c with parallels open, or photoshop.

Very impressed.
 
Works great for me

I spent a couple of hours today installing and tweaking Coolbook settings. It really does make an amazing difference. I have the 1.6 GHz processor and found it to be stable at the minimum voltage, 0.9v, with CPU tests at all speeds. Now, under normal use it doesn't heat up enough to increase the fan speed. Furthermore, even with an extreme test (running a 720p trailer in Quicktime, a full screen Youtube video, Parallels with XP running a Youtube video, and surfing with Safari) it got pretty hot (79 or 80 C) with max fan speed but never once stuttered or shut down a core. It certainly would have done so before I installed Coolbook. So, it appears that now even under maximum load that I really won't ever use under normal circumstances, the computer won't overheat and start dropping a core. Very much worth the $10!
 
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