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G5 run louder than nornal?

H

honam1021

macrumors regular
Original poster
Nov 4, 2012
242
113
So I finally found an air deflector for my Power Mac G5, I tried to play the 2 videos mentioned here, both of them play smoothly in VLC with just one problem, noise.

The noise become quite noticeable (but still quieter than w/o air deflector) when I play a 1080p video, the fans ramp up even during lightweight tasks like finder generating thumbnails for files.

This video shows a 1.8 DP G5 playing 1080p videos, the machine used in the video remains silent all the time.

Then I booted into ASD 2.5.7 and attempted to run a thermal calibration, the calibrate button was grayed out with something like "no calibration needed". Now I don't know if the noise actually comes from aging fans, or if there's something wrong with my G5?
 
Make sure that your thermostat is set to 18-20C, too high and the G5 will get hot too.
 
Don't use Artic Silver in a G5. Use only MX-4.

PS: Before heading any of the other poster's advise, always get a second opinion or do some research of your own.
 
I monitored the temps for a while, the CPU temps often goes up to 60 C then quickly drop back to 45 C, I think this is the cause of the fan noise (Perhaps it's a sensor problem)
 
honam1021 said:
I monitored the temps for a while, the CPU temps often goes up to 60 C then quickly drop back to 45 C, I think this is the cause of the fan noise (Perhaps it's a sensor problem)
Click to expand...

The G5 heats up to 60C, the fans kick in and cool it to 45C, the fans stop, the G5 heats up to 60C, repeat endlessly. Apple sure was good with the fan algorithms (sarcastic).
 
I found this in a old topic:
mac.tastic said:
Another update.

AppleFan.kext.
Stock code has it set to start to spool up up at 135*f and max them out at 144*f with very small even speed steps between and a very long delay before they spool down. I believe this is a major contribution to noise complaints.
Code: 
<key>fan-hysteresis-temp</key>
				<integer>14080</integer>
				<key>fan-polling-period</key>
				<integer>8</integer>
				<key>fan-slowdown-delay</key>
				<integer>48</integer>
				<key>fan-speed-table</key>
				<array>
					<integer>14592</integer>
					<integer>14922</integer>
					<integer>15059</integer>
					<integer>15164</integer>
					<integer>15252</integer>
					<integer>15331</integer>
					<integer>15401</integer>
					<integer>15466</integer>
					<integer>15526</integer>
					<integer>15583</integer>
					<integer>15637</integer>
					<integer>15688</integer>
					<integer>15736</integer>
					<integer>15783</integer>
					<integer>15828</integer>
					<integer>15872</integer>
				</array>
				<key>fan-speedup-delay</key>
				<integer>8</integer>

I modified the code to spool up gradually 129*f-163* then ramp up to max quickly between 165*f-167*f. Slowdown delay was cut by 2/3 from 48 to 16.
Code: 
<key>fan-hysteresis-temp</key>
				<integer>13300</integer>
				<key>fan-polling-period</key>
				<integer>8</integer>
				<key>fan-slowdown-delay</key>
				<integer>16</integer>
				<key>fan-speed-table</key>
				<array>
					<integer>13800</integer>
					<integer>14200</integer>
					<integer>14600</integer>
					<integer>15000</integer>
					<integer>15500</integer>
					<integer>16000</integer>
					<integer>15500</integer>
					<integer>16768</integer>
					<integer>17200</integer>
					<integer>17800</integer>
					<integer>18176</integer>
					<integer>18700</integer>
					<integer>18950</integer>
					<integer>19100</integer>
					<integer>19150</integer>
					<integer>19200</integer>
				</array>
				<key>fan-speedup-delay</key>
				<integer>8</integer>

These changes, along with setting performance to "automatic" have made the fans behave far more civilized. They now spool up quietly to maintain 135*f at average loads and 165*f at 100%x4 load.
Click to expand...

Instead of letting the temps raise and cool it down quickly once it reach 60 C, the custom fan profile tries to maintain the temps at 135 f (57 C). But I don't know how to apply the mod
 
I kinda solved the noise issue by removing the intake fans, the computer is a bit more toasty (around 65-70 C under load) but the it's a lot quieter.
 
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