Power Mac G4 cooling project: Phase 1 - The plan

I am excited to report that I am ready to kick off the Power Mac G4 cooling project. I have gathered all of the hardware I need in order to move forward. The goal is to incrementally upgrade the cooling fans and experiment with different intake/exhaust orientations all while monitoring the pertinent temperatures inside the case. All temperatures will be compared against the temperature of the original fans in their original locations. I will start simple by working with the existing fans and their mounting locations. Then I will move onto upgrading the existing fans while maintaining the same mounting locations. Ultimately the goal will be to add additional fans by changing the location of the hard drives and utilizing the liberated floor space of the case. Any case modification will have to absolutely look professional and clean. The ultimate goal is still in the brainstorming stages, the project will build up to that point. I want the project to be incremental so that it will benefit users of all comfort levels. I imagine that cutting up Power Mac cases may not be for everyone.

I have a hardware solution to monitor temperatures. I will be using a NZXT Sentry 2 to monitor the temperatures of 5 locations in my Power Mac G4 Quicksilver. The Sentry 2 was a pleasant surprise. It monitors two more locations than the other product I was looking at. The Sentry 2 also offers fan control in addition to temperature monitoring. The idea was to use this to temporarily monitor the temperatures during this project however I may wind up using it permanently some how. I was also able to buy it locally so I did not have to pay shipping.

I will be monitoring the...

Intake temperature

Exhaust temperature

RAM temperature

GPU temperature

CPU temperature

This will be a fun project. I look forward to sharing it with you all.


  1. It's good that you are looking into this. My Power Mac Quicksilver sounds like a 747 taking off with all the fans running. By the way, what OS are you running on your Quicksilver?

  2. Thanks! Hopefully we will be able to quiet that 747.

    Currently I am running Mac OS Tiger. My Mac OS usage is for content creation, video ripping and playback. My vision was to dual boot Tiger and Debian Wheezy, however my Acard 6290m SATA PCI card is giving me yaboot headaches that I have yet to resolve.

    1. I have a quick update. I am still unable to get yaboot to work with my Acard 6290m. I did however install Debian Wheezy to a PATA drive hooked up to the on board IDE controller. I'm not throwing in the towel by any means but I am going to call it a day. I would like some sleep.

  3. My Quicksilver is pretty much a standard configuration (purchased for $25 at an educational surplus warehouse), except for the 1.6 GHz Sonnet G4 upgrade, which is probably what is making all the noise. It has an ATI Radeon 9000 Pro graphics card which is well supported both by OS X Tiger and Debian, as is its 75 GB Western Digital hard drive. Nothing fancy here.

    I didn't want anything to get in the way of being able to test the latest Debian Jessie releases, along with running Tiger which is by far my favorite version of Mac OS X. I use it to see how Cameron Kaiser's TenFourFox is developing.

    It bothers me, though that the machine runs so hot with the fans going ALL the time. I almost think I will put the original 733 MHz processor back into it so I can leave it running as a file server for my older Macs.

    I will be interested to see what your temperature results are once you get both Tiger and Debian working.

  4. Mark:
    I got your email about the acard + debian issue. So others can read my reply also (as I will share some sage advice) I will reply here.

    While Acard have been around for years, they have always been a more under the radar type company. It is FirmTek that makes the most capable SATA controllers in my and most peoples experience. SIIG used to be quite good also, but they seemed to support Mac less and less around the late Tiger/early Leopard era. I have no personal experience with Acard at all, only FirmTek (who also makes Sonnet's SATA controllers) and SIIG. I used to have a 4-port SIIG that only supported Tiger; very odd. FirmTek fully support Mac OS and Linux, and I was easily able to make them work with BSD also.

    In the end, on Power Mac G4's at least) PATA drives running on the onboard controller will always give you the most reliable results anyway. Of my 3 active PowerPC systems, only 1 boots from a SATA card, the others (as I list in my hardware details here) are PATA.

    We're on old hardware to begin with, so any performance benefit you get from booting from SATA is really very minimal overall. Put stability first and the end result will always be better. Putting performance first is like asking for trouble, unless the hardware is part of a supercomputer or pro production company.

    As good as the FirmTek SATA cards are, I still find that in the spirit of stability they work better for storage than booting. I have found a very happy medium on my R2D3 system with SATA card booting, but it's more of a fileserver than anything. The things I do on both my main and development system rely a lot more on stability, so they boot PATA.

    If you really just use that system for a fileserver, then the CPU upgrade is just getting unneeded wear. A G3 300MHz would do just as good of a job. A system used as a fileserver is really just an advanced NAS, so the CPU is next to irrelevant. I would put the 733MHz back in if I were you. Keep the upgrade (unused) until you genuinely need the extra power, like actively using the system daily again, or install it in another tower.

    As for cooling... quiet is nice, but it can kill hardware if not done right. I personally love the sound of computers. The 3-speed Antec's I use are always on top speed. They produce 26-30db, which is audible, but not MDD-like roaring. MDD stock PSU fans could get up around 38-40db, which for many types of audio work would make it unusable.

    My fan advice:
    I prefer Antec, but because of their robust longevity, not their quietness. They are more in the middle in terms of db output. Delta, which most of this eras stock fans were, are the best at blowing lots of air, but also about the loudest. The key to quiet + still having sufficient cooling is using large fans (120mm+) that spin at a low rpm. Small fans (60mm and under) are always the loudest because they have to spin so fast to create enough CFM.

    The number one company for moving more air with less rpm is "Noctua", an Austrian company that puts steak knife type edges on their fans. They are a bit more costly, but are very well engineered with quality parts.

    My main quiet fan experience though is with "SilenX" fans, which are also very high end and are also offered in oddball sizes and depths. They are also costly. I did both my former MDD with all SilenX. They were sufficiently cooled still, and even under heavy load I had to put my ear next to the tower with the room quiet to hear it.

    So I would have to put SilenX ahead of Noctua, but you can try a combo if you like. SilenX are still at an inaudible db level and tend to blow more CFM. I also have a lot more experience and faith in SilenX.

    Hope that helps.

  5. Forgot to mention that after the full system and PSU fan replacements with SilenX on my MDD's (dual 1.42 & dual 867), the overall closed case db output was knocked all the way down to about 21-22db. Anything under 25db is inaudible territory.

    I would guess a stock Quicksilver runs at around 32db, which is about the same for all pre-MDD G4 towers. The MDD was really the only one that gained a genuine reputation for being loud with its apt "wind tunnel" nickname. But that's deserved when hitting 40db. I would say once you get over the mid-30's you're in wind tunnel mode.

  6. Some after thoughts...

    I should emphasize that instability is rare on PCI SATA controllers, and that I deal in extremes when talking about reliability. Reliability is everything to me, and in an almost unhealthy and anal manner, but it's gotten me this far personally and professionally.

    If PATA booting is 100% stable, then PCI controller booting is 99.9%. The real issue here is that the Acard controller must not support Linux, or maybe there is some preexisting firmware fix. Have you looked into firmware updates and what they offer? Since I don't have an acard myself I can't give you any 100% answers. If acard offers open firmware then you could add yaboot code yourself. I have no idea about acard firmware though. Worth looking into. I will also.

  7. I looked at the acard homepage and found a massive archive of all the drivers, firmware etc. for every card they have ever made. I noticed a few for Linux.


  8. Any plans on testing software that might cool the CPU? There's CHUD Tools for OS X:


    Also, it would be interesting to see what impact powernowd has on a Linux system. Debian banished it from their repositories, but the .deb file for the last version is kept at:


  9. It is good to be back! I was part of a team that filmed, streamed and ran audio as our shuttle mockup was placed on top of our Boeing 747 this week. It was a great celebration that required a large amount of prep work and set up.
    My workload will now be significantly lighter.

    Thank you for all of your help with the SATA vs PATA booting. I did perform Acard's latest firmware update...


    That did not alleviate the issues. I did notice that there is Linux firmware for the AEC-6293. Maybe I will be fortunate and will be able to find a firmware that will work for my 6290m. I have tabled that issue for now and have opted to boot off of an 80gb Western Digital PATA drive. I would like to revisit this issue after the cooling project is complete.

    Those are two excellent ideas. I am excited to test both CHUD and powernowd. Thank you for pointing these out.