Mac mini 2006 after upgrad to C2D fan rpm fluctuates

[aurora72]

Hello

I have upgraded the CPU of Mac mini 2006 from Intel Core Solo 1.5GHz to Intel Core 2 Duo 1.83GHz.

I have done the CPU upgrade following the online tutorials and videos, using sufficient thermal paste and I have done the SMC and PRAM resetting after the upgrade.

No problems software wise; the 64bit processes are seen to work fine on the Activity Manager.

The only problem is that the fan speed increases quickly even on normal activities like opening Google Chrome.

Here is when I open a video on Youtube. I've forgotten to include CPU on this shot but it was about 30%. 50% at most. But you see, the rpm is over 5000! You might estimate how noisy it becomes.



Other times, when I don't do any activity the rpm stays within normal (~1500-1700rpm) range. Here's a screenshot taken as I wrote this message in Firefox:



Is this fluctuation in rpm normal?

Thanks.

[DeltaMac]

The fan speed looks a little strange because the temps are not very high - I would not expect to hear the fan until higher than 70 to 75 C. Do you notice higher temps than what shows in your screenshot, as the fan begins to run at higher speed?
Maybe there's other factors than just temps.
Are both cores operating? Change the setting in your iStatPro, so you show bars for CPU cores.
How much RAM is installed? You could also show a screenshot of memory use in iStat Pro. Maybe that is spiking when the fans are running up.
Check that the cooling inlets are completely clear (vents are all around the bottom edge of the case) and that nothing is causing a problem with air flow.
Try standing the mini on edge (so the CD slot is vertical) to see if that makes a difference.

[trevor]

Quote: using sufficient thermal paste

I worry when I hear comments about sufficient thermal paste. Apple had completely wrong and even ridiculous recommendations about thermal paste--they were saying to use far too large amounts. Following Apple's recommendations for 'sufficient' thermal paste will cause it to leak out onto the other components, and potentially cause other thermal problems.

For good advice about how much thermal paste to use, look to Arctic Silver. If you follow their recommendations, you'll be fine.

Trevor

[aurora72]

I don't know if both cores are operating and I don't know where that can be set. I could not find any settings for dual cores in iStat (the version I use is iStat pro 4.92)
The RAMs are 2 x 1GB DDR2 put by Apple in factory. The RAM usage looks quite good. there's no considerable spike in RAM usage no matter how much the fan rpm increases.
Here's a screenshot when I started to watch a 480p movie in UTube for just one or two minutes(!)


I 've throughly cleaned the fins of the heatsink when I replaced the CPU. So I don't think that it's caused by blocked air flow, really. There 's just one thing that I might have overseen and it's the heatsink temp sensor's connector, I might have left it too loosely connected to the motherboard. I will check it and see if that's the case.

I cannot stand the mini on edge because I haven't put its aluminum cover back yet


Hello trevor

I have applied more thermal paste than one shown on Arctic Sliver's tutorial. But in the end, I don't think (poor) heat conductivity can be the basic cause of this very high rpm problem. That being said, I will still lessen the amount of paste soon and apply it as it's shown in tutorial, just to be sure.

Actually, I had lived a very similar problem last year when I replaced the HDD and upgraded the RAM of a factory-set C2D 1.83GHz Mac mini. After the change, its rpm would fluctuate similarly, I remember that. I had used that 1.83Ghz C2D Mac mini for years without such an rpm-problem until I upgraded it.

[DeltaMac]

If you go to the settings in iStat Pro - Sections, you'll see the choice of Graph or Bars - next to CPU.
Bars will show one bar for each core, when the Graph simply shows the combined CPU usage.

Yes, good to have the heat sink fins clean - but that is not where the airflow comes from.
Did you check along the outside bottom edge, where the air inlets are?

If nothing else appears to make a difference, then you may want to just use a utility that allows you to manually adjust the fan, without regard to sensors. "smcFanControl" works very well for that (http://download.cnet.com/smcFanContr...ml?tag=mncol;1), or HDD Fan Control - http://www.hddfancontrol.com

[aurora72]

Oh yes that's correct, I chose the bars and two bars appeared. Here is how it looks. Because there are 2 bars, 2 cores must be operating.

And surely yes I checked the outside edges they're totally clean, actually I carefully cleaned the whole machine.

I might try installing a program to control the fan. That might alleviate the noise problem, at least.