iMac G5 does DFS2 as well, btw.

> iMac G5 does DFS2 as well, btw.

I didn't know this. Fantastic to hear.

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Thanks for the help!

Some questions :
1. Did you redo the thermal calibration after converting to air cooled? This has to be done with the LCS pump still plugged in. Yes, I did plug in the LCS off to the side when I ran calibration. One cpu gave an error the other calibrated fine.
2. Do you experience the same effect ( fans running high speed ) in OSX? I don't have OSX to test. The fans are not at full speed they just are running faster and when certain items happen (like when the rno widget changes the picture) the fans spin up for a moment.
3. At what temperature does your CPU(s) run in OSX vs MorphOS? It runs around 168F to 172F, whenever it goes above 170 or so the fans spin up to bring them back down...

I really wish there was a Nactua or similar silent solution, the drowning of the fans is very annoying.

Are your fans loud in your powermac?


[ Edited by matt3 24.01.2023 - 14:21 ]

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Nice to know, will the PowerMac ever get the same treatment? I'm used to the power and can use my PowerBook if I had to, but there is a significant speed differential.

I can't wait, until the ISO shift happens and I can get a nice silent solution that has the power to do the job. I sit in a room with the box running all day and it is getting annoying...

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Replaced all the fans (minus the one wedged up by the DVD (did blow it out though) with the ones from my old 2.3 that seemed quieter. I also moved the box to another part of the office. With everything done, it seems a bit quieter, and it doesn't spin up as much. But it is still annoying, would love to find a way to silence the box...

Thanks also for the instructions on how to run ASD from USB from another thread, it worked perfectly!

In theory it should be possible to put Noctua fans in the unit. The wires are all black and coupled together to one connector (Joy...), not much on the internet about this.

Going insane right now with the noise so I'm likely going to go this direction...

Any comments or help is appreciated.

What’s the noise level? If it is the „jet mode” like you get after a minute or so in OpenFirmware, then it is nothing MorphOS could solve. It means the thermal calibration data is bogus.

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No it turns on and boots normally, with regular fan speed/noise. The fan fluctuates, most of the time is in a higher setting but will settle down other times. I'm pretty certain all the sensors and calibrations are normal just the fan spins at a higher rate (not the jet mode) to keep the system cool.

The temperature readings in MorphOS are similar to what they have always been since I started using this system. The fans however started to spin more in the last few weeks. Tried all the cleaning etc.

Right now the fan is spinning faster and the CPU temp is 168.2F, normally the fan would be at a lower setting at that temp. Only when it creeped into the 170's did it run faster or when I watched a movie. Strange...

If I open my windows and freeze myself the fans slow down to where they normally run. Snowing and cold so not interest in that :).

When I converted to air cooled, the CPU temp readings in MorphOS from the liquid cooling and with the air cooled heatsinks were identical. I put a good amount of silver on the cpu and cleaned it up...

Interesting the other CPU (claimed to be bad with calibration test) - used OF to 'disable' it, runs at 113.3f constantly. Remember in my 2.3 that the temps were much closer together...

[ Edited by matt3 25.01.2023 - 16:24 ]

MorphOS adjusts the fan speeds to stay below a fixed max temperature. If the fans are loduer than usual it means they need to rotate faster to keep the temps in check… or that they have reached their EOL.

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Thanks Jaca, I will pursue Noctua fans...

I think maybe the air cooling just isn't as effective as water cooling for the 2.7Ghz, hence the fans need to spin up to keep it cool.

Btw. my 2.5 also sits at +-160f ( 71c ) all the time.

The difference is no matter what I throw at it it doesn't rise or the fans spin up. I have left MDW's demos on loop for hours and the CPU is pegged at 100% and it doesn't rise.

How about fine-tuning fan speeds with the PowerMac7FanControl command, if you dare?

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Hmmm.

I have 2 options it appears.

1. I play with the fan speed as described in the link and hope to guess it right. It hovers around 170F so I'm worried I would cook it.

2. Put all Noctua fans in the box and lock it at the maximum spin which is 2000 rpm for the best model for the job and hope that a constant 2000 is going to keep everything cool enough.

I'm leaning on risking the second option, it seems safer to me.

Any thoughts before I pull the trigger?

170F should be just fine. Generally up to 85C is safe, even if it’d temporarily go to lower 90s (just as long as it doesn’t stay there).

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Matt, are you sure you didn't replace the fans with the wrong type? A DC fan getting a PWM signal would spin at nearly full speed all of the time. A PWM fan getting a DC signal would spin at full and turn itself off early, causing heat to build up that would then require it going to full. Either isn't good.

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Not sure that's possible. The PM fans are indeed both RPM and PWM controlled, but there don't seem to be differences between PMac models in this regard. As in: an RPM controlled fan will be RPM controlled in all models.

As for Noctua fans: matt, are you able to get Noctua fans built FOR the PMac? The connectors on PowerMac fans may look standard, but the voltages are NOT. You WILL burn your PMac if you mess this up.

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Am I sure? No not one bit:). These don't seem to be built for mac...

I was going to get a NF-A9 PWM that run at 2000RPM, from the graph on the website it is the best all around for air movement and pressure, that I didn't even know there was a difference before I went to the site.

I was going to wire them for max speed and just hope for the best. I suppose there has to be a way to get a reading and see if that is reasonable?

I did put one Nactua fan in as a test to replace the fan by the speaker. I wired it to run contstant. So far so good. This fan doesn't impact the cpus that much but was a test case...

[ Edited by matt3 28.01.2023 - 11:17 ]

Tried playing with cpu temp by setting it to 80c and nothing changes. The Fan most of the time are running at 2000rpm and are loud. Weird that the temp is 168f and it still spins about 200 rpm faster when it never did in the past.

A quick update to help someone to not loose sanity :).

I quickly cleaned up the liquid cooling unit and put it back in to compare against the heatsinks.

They run exactly the same for temperature and the fan noise is still just as loud.

So here is what I suspect:
1. My room is a bit warmer in the winter time and in the summer time I have a AC that keeps it cooler and makes it less of an issue. (I will test this for sure in the summer months).
2. The 2.7 just runs hot, so no matter what you do it will be tough to handle. I will be testing the 2.0 PCIe soon and I will see how loud it is.

Perhaps someday, MorphOS will better handle the fans in the powermac series.

MorphOS handles fans well - i've 4 PMG5 (1,8-2,3GHz) all running very silent. (CPU ~ 55-65°C).
Only one G5/2GHz sometimes backsideblower (cooles Nrthbridge) becomes loud, but not often.

This seems to be a problem of your PM. If nothing changes by setting different CPU-temps (PowerMac7FanControl), then there is something wrong with fan control on your board (or fans). Every PM I've seen, reacts to different temp-settings (incuding 2.7GHz-watercooled G5)

Are you sure, the loud noise is'nt comeing from backsideblower?

Matt,

Here is a pretty good thread on converting the fans to standard PC versions. Its not perfect, but it helps some. The 2nd link is a bit more info.

https://68kmla.org/bb/index.php?threads/whats-the-deal-with-the-fans-in-powermac-g5s-a-call-to-electronics-experts-for-help-with-retrofitting-fans.37489/

https://www.tonymacx86.com/threads/info-on-g5-fans.69889/

[ Edited by Acill 12.03.2023 - 06:31 ]

Well good news.

I finally got the 2.0 PCIe system running and it is now decent for fan noise! (Big thank you to Frank for all the help!).

The temp hangs around 115F now, a big different from the 2.7.

I will replace the fans like Acill said eventually and see if the 2.7 can be made quieter.

It is good to know for everyone that air cooling produces the exact same temperatures as liquid cooling.

[ Edited by matt3 13.03.2023 - 15:45 ]