iMac G5 and Arctic Silver 5?

Discussion in 'PowerPC Macs' started by Willy S, Dec 11, 2006.

  1. Willy S macrumors 6502

    May 8, 2005
    I´ve 2 hot iMacs G5 Rev.A out of warranty and I´m thinking if it is beneficial and possible for me to replace the thermal paste/pads with Arctic Silver 5?

    I don´t think the computer will last for long running at high temperatures, CPU at 63C and the hard drive at 57C, when idle.
  2. amd4me macrumors 6502

    Nov 19, 2006
    I was wondering this as well.
    I think some new thermal paste would help lower the temps for sure.
    Much better than the thermal pad that comes witht he computer.
  3. ReanimationLP macrumors 68030


    Jan 8, 2005
    On the moon.
    I'd do it, the Arctic Silver will drop the temps a lot. Be sure to take off the pad first though.
  4. RRack macrumors newbie

    Mar 27, 2007
    Any results of the thermal paste replacement?

    I know this thread is a old but I was just curious if anyone tried the thermal paste and what the outcome was as far as dropping the temps?

    I've got two 20" G5 iMacs...One is at apple getting yet another PSU replaced under the extention program but otherwise operates great with tolerable temps. This one is cooking! Just sitting here idle the CPU is about 60C and hard drive about 50C. When anything a little more intensive like some small flash games for my son, the thing keeps spiking up to over 80C. Apple tells me that this is a "normal" temp for these things. If so, why is the other identical iMac far cooler? My MDD G4 is a steady 52C even under rendering. I know heat kills electronics so I'm doing anything and everything to cool this thing down so it will last. Apple did tell me that they put thermal paste on several spots elsewhere on the board but wouldn't tell me exactly where. I'm also trying to find a hard drive heat sink that will fit inside this thing. Oh yeah, this one has already had the board and PSU replaced...along with a new hard drive that the the thing cooked.

    Any info would be great.

  5. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    All a bump will do is serve to annoy the crap out of us.
  6. Jimmdean macrumors 6502

    Mar 21, 2007
    Heat in a computer is a slippery slope. Even moreso in a non-standard SFF computer like the iMac. It's not like using a different transfer compound is going to make the heat disappear - it's just going to possibly transfer the heat off the CPU better. But even that isn't necessarily all that beneficial. You could end up bringing down the temp of the CPU, but raising the temp of everything else due to the heatsink getting hotter and not being able to eject the heat fast enough.
    The real trick is to let a CPU run as hot as it technically can (without erroring). Trying to get it down too low in a sff will just mean a quicker death for your hard drive or gpu. My 2 cents? If you've been ruuning ok so far just leave it alone...
  7. RRack macrumors newbie

    Mar 27, 2007
    Dropped CPU Temps over 25F!

    Just a quick update for anyone considering replacing the compound. I just finished doing this earlier. I only recommend doing this if you are pretty mechanically inclined also. These things are pretty tricky in putting back together. Especially, a little white plastic tube for the sleep light. After pulling the PSU, Fans, Superdrive, and tons of screws, I got the board out. I actually left a bunch of plugs attached down near the sleep light and sort of hinged it out towards the bottom. Then you can clearly see the screws that holds the copper heat sink onto the board. There are actually two places to replace the compound....On the processor and the opposite side of the board which is i believe the video processor. It sits against a large aluminum plate that is attached to the lower metal skeleton of the system. The compound on this one was crispy and flakey. I completely cleaned it off...threw on some silver compound...reset the SMU and PRAM...and put it back together. So far it looks like it really dropped the CPU temps. originally, it would peak at 185F or so when the processor had to think about anything...small flash games, mpegs, etc. Now under heavy loads, rendering, converting to .mp4s, it maxes out at 155F! It also seems to have lowered the hard drive temp quite a bit also....It was actually fairly easy for me and so far seems to have paid off.
  8. Alex72 macrumors member

    Jul 19, 2002
    Los Angeles
    Well, some of us don't get annoyed by thread bumps...

    Anyway, did the replacement of the thermal compound have any effect on the loudness of the system's cooling fans? Just curious, as I may end up with a May 2005 iMac G5 (Rev. B, 17", 2GHz) that can get pretty loud whenever the processor has to actually do anything...

  9. edgew8 macrumors regular


    Dec 8, 2008
    no..sadly the rpms of the fans are fixed..if its buzzing at its lowest rpm it will always buzz..However I did find a solution to fix MY iMac in this thread> and no one responded to.. I hope it can at least help you out.
  10. RRack macrumors newbie

    Mar 27, 2007
    Both of the G5 1.8s are still running strong and silent. Just also pay attention to the power supplies. They are another big problem with these things. And very expensive. I had one replaced by Apple under the recall deal and now it's starting to hiss again when booting up. I'm sure it's just a dried out cap. I know it can make it run extremely hotter than it should if it's going bad though...
  11. Alex72 macrumors member

    Jul 19, 2002
    Los Angeles
    That's good to hear, though that 2ghs one I mentioned sure can get LOUD. Were there ever any recommendations for aftermarket fans, to replace the stock Apple ones, and which might be quieter?


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