Power Mac G5 Dust Out and Thermal Paste Re-do

[AphoticD]

As a pre-new-years preparation for smashing out productivity in 2018, I decided to pull the 4 big aluminum towers out of my office and give them all a thorough clean up (plus vacuum the carpet in the dusty space they took up).

The dust inside the Macs wasn't as bad as I expected, except the Mac Pro, which had a bit of a build up on the intake fans, but does get much more run time than the PowerPCs.

As part of the process, I wanted to re-do the thermal paste on the G5s which is a job I have never done before and they all still had their factory set, cracked and powdered white silicon gunk.

So, here is the photo journal of the job; (I stopped taking photos after doing the first two machines).


1. All disconnected and setup under the back patio, ready for a clean up. Notice my home-made long Hex tool for getting the CPUs out in the early gen G5s. 1x straightened out allen key tightly zip tied onto another larger/longer one for getting down into the gap on the CPU card/heatsink. Rough, but it works.


2. The first G5 (Dual 1.8Ghz) is stripped and the PSU is removed, all the components are lined up for cleaning with an old toothbrush.


3. Inside the first PSU after blowing all the dust out. There is a little rust on the case around the fans, but nothing critical.


4. Cleaning all the components.


5. The Geforce FX 5200 lined up with the fans, HDD and SuperDrive.


6. Separating the CPU from the heatsink requires removing six small philips head screws on the plastic standoffs, then four torx mounting screws which fix the CPU against the heatsink's coldplate.


7. The aluminum coldplate on the underside of the monster heatsink with the old factory thermal paste.


8. The G5 CPU die or IHS (Integrated Heat Spreader) with the cracked and powdered thermal paste.


9. A beauty shot of the first 970 CPU after a cleanup. Notice the massive array of components around the CPU, this is matched on the other side of the PCB. I wonder if these make up the G5's "215 simultaneous in-flight instructions per CPU". A rough first count was 196, maybe I missed some.


10. A very thin layer of "Duratech" 6.5W/m-K (Silver 30%) heatsink compound. This is a very malleable paste which smooshes and spreads evenly, despite it looking like a rough surface in the (flash) photo.

Repeated again for the second CPU and the first G5 is back together again, ready to run through ASD for testing everything.

(Post to be continued with more photos below...)

 

[AphoticD]

11. Running an extension cable, power strip and my portable little 14" HDMI/VGA TV, the first G5 is being tested with ASD v2.5.8 while I get on with the next machine. The test on this Mac took about 50 minutes (2.5GB RAM total). On the next machine it took about two hours (8GB RAM).


12. Inside the second G5 (Dual 2.0Ghz) after blowing the dust out and removing the internals. This one is in great condition, with only very minor external scratches on the case and very little oxidizing on the internal plates and EMI shields.


13. Another shot of the inside.


14. The PSU in this machine is in great condition, all the dust has been blown out and there is very little sign of age. Not bad for a nearly 15 year old Mac!


15. All the components are laid out for cleaning, including the monster GeForce 6800 GT AGP GPU.


16. The Dual 2.0Ghz CPUs, ready for a teardown, clean up and a re-paste.


17. Interesting find here; although this is the same gen as the previous Mac, the Heatsink's coldplates are copper and not aluminum. Is copper a better material for cooling than aluminum? I have always found this Mac runs hotter than the 1.8Ghz, but I just attributed this to the faster clock speed.


18. A close up of the copper coldplate.


19. Here is the 2.0Ghz 970 die. I ultimately removed the plastic gaskets because of the build up of old thermal compound powder which was lodged under them.


20. While I had it out, I stripped down the 6800 GT and renewed the thermal paste and replaced the original (deteriorated) thermal pads on the VRAM pairs with new 2mm pads.

Everything went back together again and I ran the Dual 2.0Ghz through ASD 2.5.8, which failed at the CPU temperature sensor stage (the last few tests out of 100+). I tried a few times and it kept failing. I will try it again in a few days once the new paste has cured.

Regardless, Temperature Monitor readings on initial boot:
Dual 2.0 CPU A + B : ~36 - 42°C
Dual 1.8 CPU A + B : ~36 - 40°C

After 20 minutes of idle:
Dual 2.0 CPU A + B : ~46 - 48°C
Dual 1.8 CPU A + B : ~42 - 46°C

Stress test (Geekbench 2)
Dual 2.0 CPU A + B : ~ 56 - 68°C
Dual 1.8 CPU A + B : ~ 52 - 56°C

I have seen the Dual 2.0 reach 70°C when the Fastest CPU speed option is set in Energy Saver, but as I mentioned, this should settle down once the paste has a few days to a week to properly cure.

The real positive change is that there are no longer huge (~10°C) variances between CPUs (in the same machine) and they both cool down MUCH faster than before. If I crank them up and stress test and the temps go up to the top end and then stop the process, they will cool right back down to the 48 - 50°C range within seconds.

The following day, I continued on with the Dual Core 2.3Ghz G5. Stripping it down was mostly painless and the dust was minimal. This Mac was the catalyst behind doing this job because it has recently been showing huge variances between CPU core temps, sometimes sitting on CPU A: 56°C, CPU B: 72°C while idle and I have had one boot where two of the RAM slots weren't recognized, which I attributed to the high running temps.

After pulling it down and applying the new thermal paste to the single die, the Dual Core is now sitting on a cool 39°C on first boot, which goes up to about 46°C after 10 - 20 minutes, then under stress it stays around 50 - 54°C when pushed through the paces.

The final machine was the Mac Pro 2008 (3,1). I didn't do the re-paste because it sits at roughly 38 - 42°C idle and maxes at around 46°C when pushing all 8 cores, so I don't feel I have anything to worry about here. I just cleaned out the dust and put it back together again

I didn't mention earlier, but the 6800 GT in the Dual 2.0 was previously sitting around 70°C idle and would go up to 85°C! after pushing it with some 3D games. After the re-paste this now sits on 53°C at startup, 64°C after 20 minutes and 72°C tops while running Doom 3 and Halo timedemos.

The Geforce FX 4500 in the Dual Core G5 currently sits at 49°C idle and will only rise up to about 55°C when pushed, so I didn't feel the need to renew this one at this stage.

The real success story is the Dual Core 2.3Ghz G5, which I believe I have saved from a premature death. I imagine these G5s will now continue on for many more years to come.

-AphoticD

 

[swamprock]

I should do the same to my 2004 DP 2.0 G5. Although I never really push it, and the fans never come on at audible levels except at power-on, it is getting on in age. I just need the time to do the job.

 

[VanneDC]

nicely done. Ive taken many many heatsinks off intel cpus, never of my G5's. Let me know how you get on. Love the Nvidia GPU, the 6800 GT is a very nice card, as is the FX4500, but that fx5200 you've got is just rubbish. ;D

nicely written up, and very informative. Thank you

 

[AphoticD]

nicely done. Ive taken many many heatsinks off intel cpus, never of my G5's. Let me know how you get on. Love the Nvidia GPU, the 6800 GT is a very nice card, as is the FX4500, but that fx5200 you've got is just rubbish. ;D

nicely written up, and very informative. Thank you

Thanks VanneDC. Yes, the FX 5200 is an under-powered card, however still capable of getting the "supported" Core Image check in Tiger and Leopard, which is where my interest lies for this machine. I've decided to keep this G5 stock and use it as a testing platform for my software development. If I can get my app(s) to run effectively on an FX 5200, which means finding ways to optimize things, then it will run on anything. So even though it is a rubbish card, it's existence serves a purpose. As far as I know, the FX 5200 is the lowest end of Core Image supported cards. Also, it powers a 17" Apple Cinema Display which makes use of the ADC connection, that and the FX 5200 runs pretty cool with it's passive design (no fans), although it doesn't report temps to iStat Pro or Temperature Monitor.

An interesting tidbit about the FX 5200 is that apple hard-coded the Core Image framework to selectively hand off rendering to the CPU(s) when this card is detected and although the card is capable of achieving things like real-time Gaussian Blurs, the CPUs in the G5 handle these computations quicker. It does do the Quartz Extreme (compositor) rendering on the GPU and handles this fluidly. It was however an odd choice for a stock GPU in a Pro-level machine.
[doublepost=1514446891][/doublepost]

I should do the same to my 2004 DP 2.0 G5. Although I never really push it, and the fans never come on at audible levels except at power-on, it is getting on in age. I just need the time to do the job.

Yes, it's one of those "Some day" jobs, but as a Christmas gift to myself, I decided to block off the time and spend some time giving these old Macs some TLC.

To be honest, watching the "One more thing..." in this Keynote video inspired me to pull them out and admire their design...

 

[CooperBox]

Excellent job and fine write-up.

 

[VanneDC]

Ap, (hope you don't mind if I call you Ap
I remember when the fx5200 was first released, and it was capable of a lot of things that the previous gen of cards were just not able to do, however, its performance was very lack lustre, but I think its great what your using it for, and for your development, as you said, if it will run well on the fx5200, it will run great on many other cards is spot on.

congrats again for blocking some time off for Christmas to do the job, that's also very cool.

Nice machines mate, enjoy.

oh and a belated merry Christmas

 

[AphoticD]

Ap, (hope you don't mind if I call you Ap
I remember when the fx5200 was first released, and it was capable of a lot of things that the previous gen of cards were just not able to do, however, its performance was very lack lustre, but I think its great what your using it for, and for your development, as you said, if it will run well on the fx5200, it will run great on many other cards is spot on.

congrats again for blocking some time off for Christmas to do the job, that's also very cool.

Nice machines mate, enjoy.

oh and a belated merry Christmas

Thanks mate, you too! Enjoy the season. Time to eat, drink and be merry

 

[Bug-Creator]

To be honest, watching the "One more thing..." in this Keynote video inspired me to pull them out and admire their design...

What really stands out is how much of that keynote was spec-babble compared to todays which seem to mostly about how to create even more annoying facebook/instagram/*** posts.

 

[AphoticD]

What really stands out is how much of that keynote was spec-babble compared to todays which seem to mostly about how to create even more annoying facebook/instagram/*** posts.

Yes, but tech babble coming from Steve Jobs was always presented as groundbreaking and super exciting! He sure had a way of creating the vibe. Apple was his baby and he wanted everyone to know they were doing great things.

 

[z970]

Yes, but tech babble coming from Steve Jobs was always presented as groundbreaking and super exciting! He sure had a way of creating the vibe. Apple was his baby and he wanted everyone to know they were doing great things.

Unlike Timmy-boy over here, who only wants to make Apple fashionably profitable.

Depressing when you used to love the company for what they made. For what they did. Sometimes, companies can feel like collective groups of people deeply passionate about their job. Other times... It can feel like a corporation who's only purpose is to make money. Which is essentially the definition of a business, but that's besides the point.

 

[Bug-Creator]

Neither a big Steve or Timmy fanboy....

Lots of that spec-babble was really to hide the fact that PPC (Motorala) was already failing and that they had placed a dozen fans in an overengineered case to keep an extremly pricey server CPU happy in a desktop setting.


In hindsight it might have been better to do the Intel switch 2 years earlier.

 

[AphoticD]

Neither a big Steve or Timmy fanboy....

Lots of that spec-babble was really to hide the fact that PPC (Motorala) was already failing and that they had placed a dozen fans in an overengineered case to keep an extremly pricey server CPU happy in a desktop setting.


In hindsight it might have been better to do the Intel switch 2 years earlier.

Regardless of it being a hot running CPU and certainly a feat of engineering, I think I will always admire the G5. Apple in the early to mid 2000 pre-Intel era embodied everything I loved about the Mac.

 

[z970]

Regardless of it being a hot running CPU and certainly a feat of engineering, I think I will always admire the G5. Apple in the early to mid 2000 pre-Intel era embodied everything I loved about the Mac.

I feel exactly the same.

Maybe extended to the end of the 2000's.

 

[Bug-Creator]

Well my 1st Mac was a 2006 CoreDodo MacMini (all PPC Macs came later due to MorphOS) and that served my well (crippled GFX and limited RAM were the major issue).

I don't see anything wrong in my 2 2010 desktops (base config MacPro and BTO maxed Mini) and they gonna last me for a while.

The lack of real innovation really started to bite shortly afterwards.

 

[z970]

Well my 1st Mac was a 2006 CoreDodo MacMini (all PPC Macs came later due to MorphOS) and that served my well (crippled GFX and limited RAM were the major issue).

I don't see anything wrong in my 2010 desktop (base config MacPro and BTO maxed Mini) and they gonna last me for a while.

The lack of real innovation really started to bite shortly afterwards.

Post 2012?

Personally, I think everything came crashing down in 2014, then 2015. Especially on the phones and OSes.

 

[AphoticD]

In following up on an old post, I re-pasted the Dual Core 2.3GHz G5 on the weekend as it was getting high temp reports and also occasionally not booting / POSTing.

I use my Dual Core most days and during normal activities I was seeing temps jump around between 55°C and 69°C when in "Automatic" or "Highest" CPU speed setting. I saw it peak at 73°C which prompted me to pull the CPUs out to investigate.

I had re-pasted the three G5 towers using a Silver based product with a 6.5W/m-K rating and although this was fine on the Dual Proc 1.8GHz model, the DP 2.0 and the DC 2.3 weren't entirely happy. Temps would peak quickly, and although they would level out pretty fast, the peaks were uncomfortably high.

I re-pasted the DP 2.0GHz model around February with Grizzly Kryonaut (12.5W/m-K) paste. I also did the 6800 GT AGP graphics card at the same time and both have been stable. I was putting off doing the DC 2.3GHz G5 until it became problematic, which is where things got by about 10 months down the track.

I have now re-pasted the DC G5 with the last of my Grizzly Kryonaut and it has had a day or more to settle in. The running temps are much improved.

Here's idle in "Reduced" mode: (CPU Cores are at 44.2 / 44.5°C)

And now with te CPU set to "Highest", I played a looping HD 1080p video from my iPhone in CorePlayer for 5 minutes to get these temps: (CPU Cores are at 63.2 / 63.2°C)

It's also good to see EVEN readings on both cores, which up until now has been rare.

In an exciting improvement, the CPU fans are running super quiet. The DC G5 is almost as silent as my Mac Pro now. Even when pushing RAM Preview rendering in Motion or playing a game of Doom 3, the fans have remained silent.

Grizzly Kryonaut gets another +1 vote from me. I will buy a bigger tube of it next and won't ever look at another product again. It has really transformed what was otherwise a cluster of noisy G5s.

 

[stahl80]

Hi. Hope some still reads this thread. I’m about to clean my G5 and upgrade to a Geforce 6800 Ultra. So I’m also going to repaste the used 6800 I’m getting. I was wondering if someone knows what hieght of the thermal pads on the memory modules on the 6800. I see there are 1, 2 and 3mm options to buy online.

 

[AphoticD]

2mm was a tight fit, but it worked fine. 1mm might be a little better.

 

[stahl80]

2mm was a tight fit, but it worked fine. 1mm might be a little better.

Thank you! But they are suppose to be tight right? I will start with 1mm and see how it goes (might find 1,5mm...). Thanks again!

 

[stahl80]

Also serviced my PowerMac G5 today. I was hoping to lower the memory controller U3 chip heat, around 60-75c. Applied new thermal paste and replaced the broken plastic tabs, also adjusted the heatsink since it was not flush against the chip heatsink. But not a big difference, maybe a couple of degrees. Same with the CPU’s some degree maybe. But it looks shiny new non the less . The PSU was really full of dust. Now just waiting for my Geforece 6800 Ultra to arrive.

 

[AphoticD]

Great photos @stahl80 . I feel like I'm there all over again!

I find the U3 chip runs hot on my 7,2's as well. I can't remember exactly, but IIRC it was around 50-55°C on the 1.8GHz model and 55-60°C on the 2.0GHz G5. The Late 2005 (11,2) redesign certainly improved the thermal capacity, even on the air cooled models.

The heatsink on the U3 memory controller and the AMD 8131 PCI-X Controller are on the underside and, I can't recall exactly, but I believe they press up against the side of the case, allowing the aluminum casing to dissipate some of the heat.

I'm wondering if this dissipation could be assisted by adding some (extra?) thermal pads between the heatsink and the case to really push it out.

From what I understand, the overheating U3 is often the cause of memory slot failure on the G5 boards.. so any reduction of heat will help.

On that note, I tend to run my G5's on the "Slow" CPU setting (in Energy Saver) and manually bump them up to Automatic or Highest/Fastest when I need a boost. I try to avoid this on very hot days... Summer is going to be a scorcher for us here this year. Today was 35°C and it's only mid-Spring!

 

[stahl80]

Great photos @stahl80 . I feel like I'm there all over again!

I find the U3 chip runs hot on my 7,2's as well. I can't remember exactly, but IIRC it was around 50-55°C on the 1.8GHz model and 55-60°C on the 2.0GHz G5. The Late 2005 (11,2) redesign certainly improved the thermal capacity, even on the air cooled models.

The heatsink on the U3 memory controller and the AMD 8131 PCI-X Controller are on the underside and, I can't recall exactly, but I believe they press up against the side of the case, allowing the aluminum casing to dissipate some of the heat.

I'm wondering if this dissipation could be assisted by adding some (extra?) thermal pads between the heatsink and the case to really push it out.

From what I understand, the overheating U3 is often the cause of memory slot failure on the G5 boards.. so any reduction of heat will help.

On that note, I tend to run my G5's on the "Slow" CPU setting (in Energy Saver) and manually bump them up to Automatic or Highest/Fastest when I need a boost. I try to avoid this on very hot days... Summer is going to be a scorcher for us here this year. Today was 35°C and it's only mid-Spring!

Your temperatures sounds good. Under load mine is around 69-70 now but before t could get up to 75 I think. I actually don’t think the heatsink really touches the chassi but could be wrong. I I think I’ve done what I can to keep it as cool as possible without any major mods. I should try the energy setting because I think mine is on highest.

Thanks for the reply!

 

[mePy2]

Hi, thanks for sharing those photos... A vid would be appreciate too
Anyway, I want to ask you where I can find (and how to use) ASD? I’m on Quad G5, so late 2005 I think...
Best

 

[AphoticD]

Hi, thanks for sharing those photos... A vid would be appreciate too
Anyway, I want to ask you where I can find (and how to use) ASD? I’m on Quad G5, so late 2005 I think...
Best

Thanks.

Try downloading ASD 2.6.3 from the internet archive at https://archive.org/details/asd.2.6.3

I am hoping to renew the coolant in my Quad G5 when I get around to it. So maybe a video is in order...