Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Well, my plan to put one of my 2.5GHz CPU cards onto the 2.3 heatsink and run a single CPU failed. Even with all the screws removed I could not get the dual heatpipe VRM heatsink removed from the 2.5 card. It seems to be glued in place or something and I didn't want to risk bending the PCB too much.

So, instead, I decided to install the 2.3 card that came with the heatsink and am very pleased with the result. It's so quiet, I can't believe it. The fans basically never spin up past 500RPM. Even during a Cinebench run, the fans stayed at 500RPM with a peak temp of 68C. I immediately ran it again and it hit a peak of 73C about halfway through while the fans slowly ramped up to 1000RPM, then temps dropped to 70C and the fans stabilized at around 650RPM where they stayed through the end of that run and the 3rd run afterwards. Silence at last.

Obviously performance was negatively affected with a Cinebench score of 0.86. I was running the Quad in reduced performance mode anyway though to keep temps (and therefore noise) under control so I doubt I lost much. Amazingly the single 2.3 running full tilt was still quieter than the quad 2.5s in reduced mode at idle which usually had the fans running around 1200RPM.

Only real downside at this point is that the red LED labeled "CPU B Insert" is lit up all the time, even when the computer is turned off. Still on the hunt for another 2.3 heatsink.
 
The more I read about this modification, the less I want to do it given dangers of it. It’s nice to know Quad G5 can run air cooled, and not with LCS.
 
Well, my plan to put one of my 2.5GHz CPU cards onto the 2.3 heatsink and run a single CPU failed. Even with all the screws removed I could not get the dual heatpipe VRM heatsink removed from the 2.5 card. It seems to be glued in place or something and I didn't want to risk bending the PCB too much.
The vrm copper plate is simply screwed on a very thin silicone sheet. Twist gently and then it will pop. What I also did was to insert a jewel flat screw driver underneat the copper plate to pry gently. No a big issue but I understand you didnt wanted to damage your cpu. Otherwise, a quad 2.3ghz is also very nice.

My quad is dormant for multiple reason. I use my 2004 dp at the moment. My cpus were not in reduced mode and things seemed to be ok. IF when it begin its service as my primary G5 the fan are annoying, maybe I'l swap for a quad 2.3 but I'm pretty sure everything is working as it should at the moment.

Anyway, its nice to get an update on your progress 👍

edit: yes its annoying but a quad lobo with only one cpu will always have a warning led.
 
The vrm copper plate is simply screwed on a very thin silicone sheet. Twist gently and then it will pop. What I also did was to insert a jewel flat screw driver underneat the copper plate to pry gently. No a big issue but I understand you didnt wanted to damage your cpu.
That’s what I was confused about. The VRM heat sink came right off the 2.3 card with little effort, but I was twisting it as you say on the 2.5 and it didn’t budge. I was putting enough force on it to bend the PCB around 10 degrees. I tried using a flat head to pry on it but all that did was dent the PCB. I also tried a thin spudger to no avail.
 
  • Sad
Reactions: MrVitalic
@CJRhoades Could you post a picture of the back of your 2.5ghz board ? Thx.

Sure, but I've already re attached the board to the LCS as to not lose any of the screws:

tempImage6FR7mD.png


The top one is the one I attempted to remove the VRM heatsink from. I didn't bother to try the bottom one since I thought it would be the same. When it didn't come off easily like on the 2.3 board, I assumed they had used some kind of thermal adhesive instead of a normal thermal pad.
 
@CJRhoades pardon the dumb question, dut did you remove the board from the lcs? (Main 4 screw in center, all black screw, plastic clip). If the answer is yes, I dont know whats going on there. A little heat gun action could help.

The copper plate is maintained obviously by these black screw, and when you remove these, theres also plastic clip that still retain the plate.
 
@CJRhoades pardon the dumb question, dut did you remove the board from the lcs? (Main 4 screw in center, all black screw, plastic clip). If the answer is yes, I dont know whats going on there. A little heat gun action could help.

The copper plate is maintained obviously by these black screw, and when you remove these, theres also plastic clip that still retain the plate.
Yes, the board was removed from the LCS and all of the black screws on the copper plate were removed. I'm pretty satisfied with the 2.3GHz performance right now so I don't think I'm going to bother trying to swap in the 2.5 board.

Once I find another heatsink, what are the chances you'd be interested in machining them? Maybe we could work something out.
 
  • Like
Reactions: MrVitalic
Yes, the board was removed from the LCS and all of the black screws on the copper plate were removed. I'm pretty satisfied with the 2.3GHz performance right now so I don't think I'm going to bother trying to swap in the 2.5 board.

Once I find another heatsink, what are the chances you'd be interested in machining them? Maybe we could work something out.

Yes I could. PM me when your ready and have the parts.
 
I was having a problem with mutilple LCSs and I switched to air cooling . So much easier now. The temps are slightly higher but not bad . Attached picture are on idle and while benchmarking. View attachment 1760185View attachment 1760181
temps look good but the fans are spinning very fast , 2900+ rpm at idle is that correct? that must be quite noisy . I suggest a repasting with something from thermal grizzly like Kryonaut
 
temps look good but the fans are spinning very fast , 2900+ rpm at idle is that correct? that must be quite noisy . I suggest a repasting with something from thermal grizzly like Kryonaut
I am using Arctic silver but I will look for that paste you suggested :) will recalibration help?
 
it might . I plan to aircool my quad but use the 2.0 cpus instead of the 2.5 mainly because of noise . 80% of the brutal ppc number crunching power compared to the 2.5 but silent!!
 
it might . I plan to aircool my quad but use the 2.0 cpus instead of the 2.5 mainly because of noise . 80% of the brutal ppc number crunching power compared to the 2.5 but silent!!
I calibrated today but it seems to be about the same . I am going to find some of that Kryonaut thermal paste to try . Also my heat sinks are the silver plated on the bottom . I did order some copper plates once for better heat transfer. The main noise went down when changing the video card from an ATI x1900GT to a quadro fx 4500. Not to mention much better frame rates on games that require the extra texture memory such as quake 4 on ultra .
 
  • Like
Reactions: Nikolaosth
yes yes i need to find my self a quadro 4500 as well but it aint easy to find one reasonably priced here in europe.
 
A simple update on my proposal of machining heatskink. I cant atm because I changed workshift and I'm not alone in the shop at night anymore like I was a couple months ago. Sorry :/
 
For your interest, I found a compatible ssd. With shipping, ordering a ssd from owc cost a lot (about 130$). I’m glad I found an alternative. This is my bootcamp drive but I’l clone it on a platter hard drive. I tried a kingston ‘ssd now V300’ but it doest appear in 10.5. Note that I’m always using western digital velociraptor caddy for my ssd, because they are cheap, all aluminium and they look very cool. View attachment 904075
Can you confirm if this is the version with Silicon Motion SM2256S controller as "This model is available with different controller and memory modules."


Just a quick note about the liquid cooling system on the quad G5. Not to take away from the really cool accomplishment of OP but the dual pump LCS is pretty reliable. No o-rings to go bad and no leakage as the system is a closed loop. The cooling blocks do eventually clog up but that can be taken care of by draining the system and refilling it making sure to purge the loops of any air. That's what I did with mine and I'm getting consistent mid 20s to low 30s Celsius temperature at idle.
Did you refill with that nasty Apple stuff or distilled water or whatever PC LC uses?
 
Eh whats up ? I’m sorry I’m on many social network, mainly twitter and others So I’m rarely checking on macrumors.

I finally made the switch from my 2004 dual processor in favour of the quad G5. So no more fan micro bursting.

Its a rocket, I’m very pleased. Its the first time I’m really using this G5. Sporting 8gb of Nyana ecc ddr2 (blue stick), a modded ATI Radeon x1900 with a swapped cooler from a macpro x1900 and of course a compatible sandisk ssd.

On top of my sandwich 😆 I replaced my 2010 5.1 single tray 6 core for a flashed 2009 4.1 12 core. Also a freaking rocket, a totally different machine.

Last month I found two Apple 30’ cinema display, so I’m very happy with my setup atm. I love these old mac !
8E451B08-5082-43BA-9C45-403DD3A0FB8F.jpeg
162736B1-F631-4738-AC38-D9475A976509.jpeg
A81C499E-13F7-4F63-A415-278FACB2C91D.jpeg
88D3BED1-99A0-4BB7-810B-4EF214720B26.jpeg
 
Last edited:
Can you confirm if this is the version with Silicon Motion SM2256S controller as "This model is available with different controller and memory modules."
I’l check tomorrow when I wake up. I know these ssd are tricky to work on G5. I’l post a detailed picture.

Maybe you already found one that is working.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.