Throttling doesn't prevent laptop overheating if running a very demanding application

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Launch Parallels
2. Run CPU Burn-in tool (http://users.bigpond.net.au/CPUburn/)
3. Wait a minute

(You can reproduce this with photoshop CS2 as well, any application that'll
stress the processor)

What is the expected output? What do you see instead?

I was expecting to see the CPU throttled down to prevent the system from
overheating, however it instead opens up the processors to full speed,
which quickly overheats my quaint little laptop.

What version of the kext are you using? On what kernel and processor?

I'm using the latest version of the kext (1.4.0) using the ModBin Kernel
(9.2.0, I believe - I don't know how to check it to be sure) with an Intel
Core 2 Duo T5500 (1.66GHz).

Please provide any additional information below.

I installed this Kext to get my hackintosh laptop's overheating under
control, and it's doing a very good job. Before I was using this Kext (or
Tuxx SpeedStep.App) my system would idle around the 70-75 degrees Celsius,
now it idles around 55 degrees. With practically everything I do, this Kext
did the job. 

The only downfall is when I'm running something that's maxing out the
processor, speedstep gives it more processor when it really should be
giving it less (at least in my experience with it) - if I throttle the
processor down manually with Tuxx's Speedstep.app, the processor stays
cool. Although I don't believe its implemented, it would be very useful to
have the kext monitor the processor temperature, and give it a temp limit
for running at the maximum speed setting.

Kudos for your solid development... this is the best speedstep solution
I've found yet. This, with a temperature gauge
(http://www.bresink.de/osx/0TemperatureMonitor/details.html) and a
throttling app like Tuxx SpeedStep is a viable solution for people with
shitty cooling systems. However, if you could extend the Kext to also make
sure the processor isn't about to melt through my desk in the process, it
would be perfect.

Thanks!
Doug Hatcher
superterran

Original issue reported on code.google.com by superter...@gmail.com on 25 Oct 2008 at 6:51

[GoogleCodeExporter]

This is not as much a bug report as a feature request. Great suggestion to use 
temperature as an additional 
parameter - it's been on my to-do list. The whole idea of SpeedStep is to 
provide more cpu cycles/sec when 
the demand is high, instead of the other way round. So it does exactly that - 
opens up the CPU if a processor 
intensive app is running, giving you a balance between power 
consumption/dissipation and performance. If 
you were to clamp it to some minimum value, one could ideally just use a slower 
processor or use a fixed 
throttle as you suggested!

There are however 2 ways to prevent overheating: 1) Undervolt the processor. 
This is generally not 
recommended unless absolutely necessary, and 2) Underclock the processor on 
high temperature even if 
demand is high (as you suggest).

Method 1) Undervolting is already implemented.
Method 2) Force Underclocking on high temp is being worked on for next version.

Original comment by mercurys...@gmail.com on 30 Oct 2008 at 2:48

• Changed state: Started
• Added labels: Component-KextLogic, Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Yeah, I'm all sorts of aware that it's kind of contrary to the function of 
SpeedStep,
but it seems like it's the best place to work on a fix. 

It does a great job though. right now, my laptop's a 55 degrees, which before I
installed it's baseline was 70 degrees. If I'm in Photoshop, it's all over the 
map,
but it rarely gets in to the red. Generally, everything I do it can handle at 
1Ghz,
and when it steps up the performance, it only needs it for a few moments - 
which is
perfectly fine. It really only gets hairy when I'm trying to do something with 
by all
rights I should be doing on an intel iMac or a Mac Pro. It's just that my 
HacBook is
exponentially faster than my G5 and I kinda miss having the performance of a 
dual
core intel processor.

Maybe a decent solution, so you don't have to overcome the issue or tempeture
monitoring, would be to step it back by about 300Mhz after a few minutes of 
stressful
activity, and then after a few more drop it another 300MHz or so. it seems to me
(and, honestly I don't know) that it would be far more processor intensive to
constantly monitor the tempeture, however you obviously have the code developed 
to
monitor processor utilization already. it would  take some doing to implement a
temperature gauge. Having said that, Temperature Monitor
(http://www.macupdate.com/info.php/id/12381) already have a Kext that does 
exactly
that - maybe it would be easy to get your kext and it to work together instead 
of
having to solve the whole monitoring temperature problems within your kext. I 
would
be happy to play around and come up with a decent idea on how the code should
regulate it for optimal efficiency.

your Kext has dramatically increased my battery life; it must be 20-30 percent 
better
than it was before. 

I'll keep my eye on your progress, and I would definitely be interested in 
testing
your next build. this Kext, so if there's anything I can do to help, let me 
know. I
don't know shit about xcode  (however I've been trying to remedy that), but i'm 
a
damn good beta tester.

Thanks for your effort and taking my request seriously. Your Kext has genuinely 
been
the difference between making this a dual boot hobby and a single OS mac clone. 

Original comment by waccamaw...@gmail.com on 30 Oct 2008 at 5:29