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Excellent write-up on LCS Servicing, Quad G5


Well-known member
There are a handful of us who like the G5, and want to keep the machines running. The rest of you can ignore this post!

The following link could be of use to someone trying to quieten a Quad G5, and to prolong its life: http://www.saunalahti.fi/~holindho/g5-quad-v1-lcs-repair.html . Notice the graphs at the foot of the page, as 10ºC lower CPU temperatures at idle and 40ºC lower under load would make all the difference in dealing with fan noise. There are some further links re. cooling systems in the G5 at the bottom.

I have serviced three air cooled units (essentially just thermal grease renewal and cleaning out dust, followed by recalibration) with excellent results, and these are very easily done (contrary to what some people think), but the liquid cooled systems especially make people shudder. The writeup takes much of the complexity out of the whole question.

I believe that there were two LCS systems in the Quad G5, so be aware of that — your LCS may differ. All the same, the author has documented not only the basic plumbing and mechanicals, but crucially, the presence of sediments in the radiator fluid used after several years, leading to clogged filters. There will be a related need to clean out the radiator and clean or renew the hoses.

As in your car's cooling system, the lifespan of radiator fluids is limited, and when sedimentation occurs, the works are bound to get gummed up. The key thing in the LCS is to keep it running optimally, as the temperature thresholds are really rather slender, so this is good to know about.

My "new" Quad G5 is still working well, but it could still afford to run at slightly lower temps, so methinks I'm going to service it sometime over the coming months.



Well-known member
There is only a handful of people that like the G5?

I didn't think they were that terrible.

I would assume with a Lights dimming Quad core G5,

You should still be able to do some slightly useful things with them.


Anonymous Freak

Well-known member
The late 2005 model carried a 750W power supply, which is a lot, but there are PC power supplies (and many server power supplies) that are much larger.

My dual-proc server at home has a dual-800W power supply. (It's meant to be for redundancy, so it should only draw 800W max.)



Well-known member
Original link is dead as of 30 Oct 18 and apparently since at least 2017. Archive has it from April 2014. Does someone [read: admin-type person] want to preserve it or copy/paste the info here?



Well-known member
I recently picked up a Dual 2.5Ghz G5. Of course all the coolant leaked out corrosion has only affected both cpus and I cleaned them up. Board is still mint and the PSU although Dirty seems fine. I need to figure out how to rebuilt the cooling system as well, mine differs slightly from this post.