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-   -   Cool Your iBook by underclocking video card???? (http://www.mac-forums.com/forums/apple-notebooks/11556-cool-your-ibook-underclocking-video-card.html)

eburness 12-08-2004 04:20 PM

Cool Your iBook by underclocking video card????
 
Ok guys,

Here's an idea. I've noticed the iBook has a tendency to get hot at times. Mine can hit 60C+ under the right (or wrong, depending on perspective) conditions. However, the GPU temperature of the Radeon 9200 is always hotter, and ranges between 50C at the low end and 65C under bad conditions. My question is then, since most of us don't use our iBooks for games or intense graphics work, is why do we need our Radeon's to run at the mhz speed that they do? A desktop version of the 9200 runs around 300mhz for both the GPU core and RAM, so I'm assuming the notebook version is around that (perhaps slightly lower). But I don't think we need that kinda of mhz horsepower for the the video card. The sysem would run the exact same at a video GPU and RAM speed of, say, 200mhz, and our iBooks would run both cooler and longer (fewer mhz means both less heat and power consumption).

Now, in the windows world there are many programs to do this kinda of trick, even for notebooks. The program Powerstrip is the best one, though I don't think there is a OS X version (could be wrong though). Does anyone know of a program that lets OS X users adjust their video card settings??

Aptmunich 12-09-2004 05:42 AM

No I don't, but I would say that OS X uses the graphics capabilities to power quartz extreme that display effects such as Exposť, the genie effect, resizing etc...

So if you could slow the GPU, you might notice slowdown in general system graphics performance...

eburness 12-09-2004 08:43 PM

Quote:

Originally Posted by Aptmunich
No I don't, but I would say that OS X uses the graphics capabilities to power quartz extreme that display effects such as Exposť, the genie effect, resizing etc...

So if you could slow the GPU, you might notice slowdown in general system graphics performance...


Ok all, so update on the underclocking of the iBook's Radeon 9200. I found a program called "ATIccelator II" which adds a systems preferences pane that allows you to raise or lower your ATI graphics card's GPU and memory clock speeds.

I discovered the default settings are 183mhz for the GPU and 190mhz for the VRAM. I downclocked both of these to 100mhz (roughly a 45% drop-off in clock speed for both). First of all, I noticed zero stability problems through a/b 12 hours of uptime. Secondly, I noticed no lag in the general system performance. My guess is that while some older powerbooks and iBooks, with less powerful GPU's and less VRAM might have rendering speed issues at a lower clock rate, the newer ones are more than powerful enough to run smoothly even while downclocked. Thirdly, I noticed a/b a 12 minute increase in battery life, from a/b 4:03 hrs to right at 4:15 hrs. A small increase, but an increase nonetheless.

If anyone else wishes to try this please post your results here.


iBook G4 1ghz (1.07ghz in system info)
768mb RAM
30gb HD
Airport Extreme
OS X 10.3.6

Amd AthlonXP 2600+ @ 2.2ghz (10x220mhz)
Epox 8RDA+ rev. 2 mobo
512mb PC2700 @ 220fsb
GeforceFX 5950 Ultra
60gb HD / Floppy / DVD-RW+/-
WinXP Pro

eburness 12-09-2004 08:52 PM

Quote:

Originally Posted by eburness
Ok all, so update on the underclocking of the iBook's Radeon 9200. I found a program called "ATIccelator II" which adds a systems preferences pane that allows you to raise or lower your ATI graphics card's GPU and memory clock speeds.

I discovered the default settings are 183mhz for the GPU and 190mhz for the VRAM. I downclocked both of these to 100mhz (roughly a 45% drop-off in clock speed for both). First of all, I noticed zero stability problems through a/b 12 hours of uptime. Secondly, I noticed no lag in the general system performance. My guess is that while some older powerbooks and iBooks, with less powerful GPU's and less VRAM might have rendering speed issues at a lower clock rate, the newer ones are more than powerful enough to run smoothly even while downclocked. Thirdly, I noticed a/b a 12 minute increase in battery life, from a/b 4:03 hrs to right at 4:15 hrs. A small increase, but an increase nonetheless.

If anyone else wishes to try this please post your results here.


iBook G4 1ghz (1.07ghz in system info)
768mb RAM
30gb HD
Airport Extreme
OS X 10.3.6

Amd AthlonXP 2600+ @ 2.2ghz (10x220mhz)
Epox 8RDA+ rev. 2 mobo
512mb PC2700 @ 220fsb
GeforceFX 5950 Ultra
60gb HD / Floppy / DVD-RW+/-
WinXP Pro




I forgot to add that I noticed a/b a 6C drop in the GPU temperature and a 2C degree drop in the CPU temperature when downclocking both the GPU and VRAM

McGuillicuddy 12-10-2004 05:53 AM

Wow. 183/190 is awfully weak. Has anyone tried to overclock the 9200? Surely it can handle higher settings than that.

rman 12-10-2004 10:49 AM

Quote:

Originally Posted by McGuillicuddy
Wow. 183/190 is awfully weak. Has anyone tried to overclock the 9200? Surely it can handle higher settings than that.

He did not overclock, he underclocked. That is why you see the numbers 183/190. :)

McGuillicuddy 12-10-2004 11:48 AM

I'm aware that he underclocked; he underclocked to 100/100, but the default settings are 183/190 (i.e. that's what we're all currently running with) which I thought was a bit weak.

rman 12-10-2004 02:53 PM

Rereading his post. My bad.

eburness 12-10-2004 09:45 PM

Quote:

Originally Posted by rman
Rereading his post. My bad.


Ok, new news. I've discoevred the lowest u can underclock the card before the screen starts looking weird is a/b 25mhz for the gpu and memory clocks. Anythign above that is fine. System performance did seem a bit less snappy. So I've settled on 120mhz for both the GPU and VRAM.

Does anyone know of a way to dynamically underlock the system CPU or anythign else that might keep the iBook running cool?

Aptmunich 12-11-2004 03:11 AM

Well, I believe the settings for processor performance in the energy saver preferences do slow down the processor to save energy, but once again - I don't know of any utility to actually scale down the speed in Mhz...


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