Reapplied Thermal Paste on DC 2.3GHz G5

noodle654

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Original poster
Jun 2, 2005
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I have been trying to make my DC G5 run cooler, but nothing seemed to work very well. After taking apart my DP the other day, which had a bad logic board, I decided that reapplying the thermal paste to my DC might be a good idea because it is an 8 year old computer and probably could use some new paste.

I thought I would share my results with you all here, and I have attached some photos because I know everyone loves to see some good ol' photos.

I used arctic silver 5 for thermal paste, and I cleaned the area with 92% iso. I then let the chip dry under a warm lamp for 30 minutes. After putting everything back together I ran ASD to recalibrate the system, below are my temperature results.

Temps before:
120F-125F (49C - 52C) at idle
130-135F (54C-57C) running weather software

Temps after:
108-112F (42C - 44C) at idle
116-120F (46C - 49C) running weather software



Not much paste there!


Heatsink with old paste


Almost clean!


Prepped heatsink with very small amount of AC5, notice the haze color to it


Ready to go with AC5 on it. I used smear (using saran wrap). There was a perimeter black plastic around the die which I kept in place


What a heatsink

Well, overall this was a complete success. I achieved much lower temperatures and more even temps across both cores, before I had about a 5-10F degree spread. I highly recommend it to all G5 owners if you want to cool down your summer time heater.
 
Last edited:

Lil Chillbil

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Jan 30, 2012
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I always told myself that someday I would start up a dual processor g5 2.0ghz with no heatsinks and fans taped stopped. and see what happens
 

wobegong

Guest
May 29, 2012
418
1
Interesting, that's quite a drop in temp - Maybe technology has moved on since the PM was built and thermal paste is a much better conductor today.
If it wasn't such a pain to do I might have been tempted to have a go myself as a weekend project....
 

skinniezinho

macrumors 65816
Jan 1, 2009
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Portugal
Interesting, that's quite a drop in temp - Maybe technology has moved on since the PM was built and thermal paste is a much better conductor today.
If it wasn't such a pain to do I might have been tempted to have a go myself as a weekend project....
Manufacters always poor thermal paste.
In my opinion every single computer can always benefit from good thermal paste.
 

noodle654

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Jun 2, 2005
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Interesting, that's quite a drop in temp - Maybe technology has moved on since the PM was built and thermal paste is a much better conductor today.
If it wasn't such a pain to do I might have been tempted to have a go myself as a weekend project....
It is actually pretty easy. I did have to wait a week for a 7" 4mm ball hex screw driver to come in the mail, got one on eBay for $4. If you take a look at the service manual for your G5 model, you will see that it is pretty straight forward. Total time actually working on it was less than 30 minutes. If you feel comfortable enough I would highly recommend it.
 

noodle654

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Jun 2, 2005
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Ok thanks, might give it a go.
Just want to point out that the DC/Quad require a 7" long (or larger) 4mm ball hex screw driver, which isn't available anywhere really, to take apart the heatsink. Only place to get one reasonably cheap is eBay.

However, if you have an earlier G5, you should be able to take apart the processor/heatsink with basic tools (hex drivers, philips head).
 

wobegong

Guest
May 29, 2012
418
1
Just want to point out that the DC/Quad require a 7" long (or larger) 4mm ball hex screw driver, which isn't available anywhere really, to take apart the heatsink. Only place to get one reasonably cheap is eBay.

However, if you have an earlier G5, you should be able to take apart the processor/heatsink with basic tools (hex drivers, philips head).
Much obliged :)
 

MisterKeeks

macrumors 68000
Nov 15, 2012
1,832
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I should do this. I have a dual 2.7, and the temps can be in excess of 190 Degrees F (87/88 C) when doing very computationally intensive stuff (Macports, GCC). Not sure whether the paste or LCS is at fault. I suppose that I would find out.
 

skinniezinho

macrumors 65816
Jan 1, 2009
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I should do this. I have a dual 2.7, and the temps can be in excess of 190 Degrees F (87/88 C) when doing very computationally intensive stuff (Macports, GCC). Not sure whether the paste or LCS is at fault. I suppose that I would find out.
first try the thermal paste...cheaper =)
I had an HP DV9575ep that from new was hot like hell, as soon as I changed thermal paste: Bang a totally cool computer.
 

noodle654

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Original poster
Jun 2, 2005
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I should do this. I have a dual 2.7, and the temps can be in excess of 190 Degrees F (87/88 C) when doing very computationally intensive stuff (Macports, GCC). Not sure whether the paste or LCS is at fault. I suppose that I would find out.
Wow 190F? That is really high. I got mine to top out around 170F, but the fans kick on and it cools down fairly quickly. It was pretty easy to notice that mine needed new thermal paste because of the large difference in temperatures between the two cores. My spread before was up to 10F, after reapplying the spread is less then 2 degrees.

I would say to totally do it, from the looks of mine there was nowhere near enough thermal paste on the die, and I took the heatsink off while it was still warm.

If you do reapply the paste, show your work/results in the thread...it would be interesting to see some comparisons.
 

MisterKeeks

macrumors 68000
Nov 15, 2012
1,832
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Usually after it peaks at 195/196 fans kick it back to 170/180. Can you link to where you got the screwdriver?

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I always told myself that someday I would start up a dual processor g5 2.0ghz with no heatsinks and fans taped stopped. and see what happens
Why on earth would you do that? Nothing noticeable would happen, and you would ruin a good computer.
 

noodle654

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Jun 2, 2005
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jdryyz

macrumors regular
Jun 12, 2007
218
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Thanks for posting this! I would like to do the same for my 2.3GHz Dual Core. Are there any precautions with separating the heatsink from the CPU? It looks straightforward to me.

Also, how critical is it to run ASD afterwards? I thought that is only necessary if adding or replacing a CPU (with new). ASD is not built-in to the PPC Macs, correct? It is a bootable disc?
 

666sheep

macrumors 68040
Dec 7, 2009
3,626
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Poland
Are there any precautions with separating the heatsink from the CPU? It looks straightforward to me.
It is straightforward. Few phillips screws and 4 hex ones. There'a also a plastic clip on small "helper" heatsink.



Also, how critical is it to run ASD afterwards?
Not at all, especially when you have only one CPU (no possibility to accidentally swap CPUs).
 

noodle654

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Original poster
Jun 2, 2005
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Thanks for posting this! I would like to do the same for my 2.3GHz Dual Core. Are there any precautions with separating the heatsink from the CPU? It looks straightforward to me.
No precautions, it is pretty simple to do. I recommend getting the G5 warmed up first before you take the CPU apart, makes it a little easier.

Also, how critical is it to run ASD afterwards? I thought that is only necessary if adding or replacing a CPU (with new). ASD is not built-in to the PPC Macs, correct? It is a bootable disc?
Not necessary, just did it to check my works. I did run the thermal recalibration though, figured it couldn't hurt after doing everything.

Hope it goes well!
 

honam1021

macrumors regular
Nov 4, 2012
220
65
Lap the heatsink base and you'll have even better temps!

Also do the same to my 2.0 GHz DP, but I didn't run the calibration software since my air deflector hasn't arrived yet.
 

MysticCow

macrumors 6502a
May 27, 2013
833
388
It is straightforward. Few phillips screws and 4 hex ones. There'a also a plastic clip on small "helper" heatsink.
What if you were a clutz, like me, and break the plastic clip?

DISCLAIMER: I have not broken the clip and no G5's were harmed in the making of this post.
 
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