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Limiting CPU usage - How

H

hotshotharry

macrumors 6502
Original poster
Sep 6, 2007
315
0
Does anyone know of a way to limit individual applications and cap their max cpu usage.

Like say i want to restrict handbrake to 70% cpu usage max, is there an option or something?

The reason i ask is because seeing processors temps of 70C are a bit concerning lol, i dont mind if it takes 10 mins longer :) and sometimes i work in hot areas and the cpu temp can be 60C sitting idle with fan running flat out !

Thanks
 
I searched to find out this and failed, and seeing as it already was a thread on this i figured i'd bump it instead of making a new.

I remember I could do it with the terminal, but i do not remember how.
 
yeah I am concerned about heat in my macbook too... after downloading/having SMCfan running, and forcing my macbooks fan to run about 200RPM's faster then regular idle my macbook went from 56-60 celcisu idle, to 50-54 celsius at idle. Which im content with.

BUT whenever i play games or pretty much anything process intensive, I get into 70-75 celsius. I HAVE even seen it running 80 a couple times, usually when it gets that hot i quit what im doing and let it cool down im not sure but i think i've heard the core2duo heat limit is 90 degress celsius??

If someone can confirm that or not, but it still worries me to see my macbook running so close to the max heat.
 
I decreased my cpu temp with downclock via software now my laptop run at 58 / 60 degree using coolbook application.

Hope can be useful for you.

Cheers
 
Core 2 Duos have a processor temp of 100 deg C. Relax if you think 70deg C is hot. The processors in the laptops were made to handle that much heat. This isn't a desktop processor nor a desktop here. Don't sweat on the CPU being 70 deg C. Sweat when it hits 100+.
 
ayeying said:
Core 2 Duos have a processor temp of 100 deg C. Relax if you think 70deg C is hot. The processors in the laptops were made to handle that much heat. This isn't a desktop processor nor a desktop here. Don't sweat on the CPU being 70 deg C. Sweat when it hits 100+.
Click to expand...

Indeed. The Core Duo and Core 2 Duo processors have a maximum junction temperature of 100 degrees Celsius. In other words, if you go over your processor will malfunction and may sustain irreversible damage.
 
m1ss1ontomars said:
Indeed. The Core Duo and Core 2 Duo processors have a maximum junction temperature of 100 degrees Celsius. In other words, if you go over your processor will malfunction and may sustain irreversible damage.
Click to expand...

My CD can get to 120°C with no problems, i think the hardware emergency shutdown is somewhere around that number.

anyone found a fix to this im very interested to fix it.

i did find this

http://forum.handbrake.fr/viewtopic.php?t=2046

which (when you use x264 and type threads=1 into the advanced options in handbrake) makes it use only 1 CPU, users of it still experienced the same heat readings and it hardly reduced the FPS at all..
 
Like a couple have already stated - this is NOT a problem. The chip works at much higher temperatures without any problems. I assure you - you will not help your processor in ANY way by running it at 60C instead of 70C, so stop worrying about it.

Have a cold one and cool yourself off instead ;).
 
My computer usually hovers around 80-82 when being pushed. It's a mbp13" 7.1 2.66ghz c2d with a m320 graphics chip (also the northbridge) I just started a port upgrade outdated and it's hit 85. While gaming and using the gpu heavily, if I hit 83-85 I will begin to see relics and texture errors in the graphics. It's a set of white squares roughly a half inch wide that flicker and get in the way of enjoying the game. If it's a shooter, usually no problems. If it's a text based interface such as EVE online, it gets rather hard to read important information on screen. In any event restarting the game after letting it cool down is the way to go.

I've looked at cpulimit as a solution. It looks like there's an attempt to port it to mac but I haven't found the result of this. (It does its job simply by sending signals to the target process)
 
hotshotharry said:
Does anyone know of a way to limit individual applications and cap their max cpu usage.

Like say i want to restrict handbrake to 70% cpu usage max, is there an option or something?
Click to expand...
On a Quad-Core add this to the advanced parameters (HandBrake):
Code: 
:threads=3
or this
Code: 
:threads=2
on a Dual-Core machine.

HandBrake (HB) uses a lot of SSE2/SSE4 instructions, which saturate the memory I/O system (even on SB-machines), so that virtual cores (HT) are not able to improve the performance of the x264 encoder in HB. That means, you should use
Code: 
:threads=NumberOfPhysicalCPUCores
for maximum performance and
Code: 
:threads=(NumberOfPhysicalCPUCores / 2) + 1
for lower temperatures (RAM & CPU semiconductors). +1 is for the I/O thread.

Some other tricks:
Use the "renice" command (Terminal) to give HB a lower priority:
Code: 
sudo renice 19 PID
"PID" is the process id, which you can find via Activity Monitor or via the
Code: 
top
command in a Terminal window.

You can reduce the CPU usage of some apps via the Terminal, if you know you do not need them (a web browser for example):
Code: 
kill -SIGSTOP PID
reduces the CPU usage of the process with the process id "PID" to zero.
Code: 
kill -SIGCONT PID
resumes the process with the process id "PID".
 
Hi so I don't know where to input the advanced options to control HandBrake's CPU usage... is it in the advanced x264 option string? If it is, do I have to re-input the ":threads" command per source or can I plug it in once and have it apply to all?
 
Last edited:
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