Mac mini G4 cooling solutions?

[mailcty]

I've recently decided to splurge on a used Mac mini G4 alongside some components to upgrade it a bit (1 GB RAM, a 128GB mSATA-to-IDE SSD, and most recently an Edirol UA-1EX USB audio interface), and while it does actually boot faster and perform better than before, I can't help but be concerned about how it cools itself. Being one of the silent upgrade models with the 1.5GHz G4 and such, I was hoping that Apple changed the minis enough to where their cooling system is acceptable if not more than so. However even if I play games as light as Diablo, SimCity 2000, or Stay Tooned on my mini G4, all through this site's 9.2.2 v8 by the way, the fans raise to 100% to the point where the mini eventually powers off from what seems to be overheating. I did raise my mini with two CD cases in hopes that the vents below can cool better, but the fan and heat behavior remains when using both my OS 9 and OS X Leopard partitions. I even opened my mini up several times just to dust it enough to where it looked immaculate, yet I still get the fan/overheating after enough activity. At the very least, leaving the mini to idle doesn't lead to this issue right away yet and does help cool it after a few minutes of active use.

Upon further research it seems that the mini G4 is actually notorious for having bad or loud cooling, yet before I've done the RAM and SSD upgrades to my mini, the fan/overheating issue didn't happen as severely compared to now, which is a bit concerning. Reverting the RAM back to 512 MB certainly didn't lessen the chances of this happening, and I'm not interested in continuing to use the 80GB hard drive it came with. I could have low-key messed up in the process of disassembling it the first time but its hard to tell considering that several others have had the fan/heat issue without making any upgrades. I've heard that Mac hard drives have some sort of thermal controller built in them, hence why the mini G4 isn't so sure how to cool itself with the SSD? I'm not 100% sure on that though since that feature seems to have started with Intel Macs. But in terms of improving the cooling for the mini G4, I've heard that placing it vertically helps, or raising it enough to where the air has enough space to exit, but what about other tried-and-tested solutions? Reapplying the thermal paste often helps for any old computer (any guide out there specifically for the mini G4?), or maybe I just need to revert back to a Mac HDD. But seeing as others have had varied results with the mini G4's cooling and overheating then and now, what are some solutions which can fix this flaw of Mac mini G4 pretty well?

tl;dr - As many including myself have suffered from the fan/overheating Mac mini G4, what are some efficient solutions out there to fix or prevent this from happening often? Reapplying the thermal paste to the well-covered CPU? Just leave it standing vertically? Placing some ice below it? Not using it like a Power Mac?

[FdB]

G4 Minis run considerably cooler than the first Intel-based Minis. And… with an SSD installed in the G4 temps should be reduced - over those G4s with the standard HD. If the fan speed quickly goes to maximum and the mini shuts down, the processor probably needs new heatsink paste or you’ve some other heinous problem. (A thorough cleaning of all the blades on the fan’s squirrel-cage too, while you’re at it.)

Careful compression of the CPU’s heatsink’s four individual, black plastic, expansion “wing” mounts (on the backside of the motherboard) with small needle-nosed pliers… along with a slight pressure - pushing them one-at-a-time back through the mobo, releases the heat sink. (Mind those springs.) If careful, these original black plastic/nylon mounting shafts can be re-used. If not, then small nylon nuts & bolts from the hardware store can be used as replacements. Carefully remove, clean and replace the heatsink paste and then reassemble. It’ll run cooler and more stable.

The addition of four 1/8” thick rubber “bumper feet” to the bottom four corners of mini’s bottom pad increases overall air flow. Fans here in minis (ranging from the 1.25 to the 1.5) almost never run @ maximum RPM, nor are they ever noisy. The 1.52 here has an SSD… running cooler and quieter than those that do not… and none of them stand vertical.

Anyone else have a G4 mini that runs so hot that it shuts itself down?

[mailcty]

Just cleaned my mini G4's CPU and applied some new thermal paste to it, and it appears that this actually helped in Mac OS X. While the fan expectedly operates at its highest speed during a complete Xbench test, the mini surprisingly wasn't freaking out while playing a few minutes of Marble Blast Gold and in fact seemed to be decently cooling itself as its able to reach idle cooling much faster than before.

The startup disk chooser (when holding Alt-Option while powering on) and Mac OS 9.2.2 however seem to be pushing the fan pretty high still, even when playing Snood in OS 9. The system doesn't actually start cooling until I activate Sleeper's sleep mode. I also didn't continue long enough on Snood in case its actually wearing out the CPU and new thermal paste severely and am continuing to test other games and software in OS 9 on my mini G4.

Thanks for the suggestion either way FdB. Here's hoping this does work out in the long term.

Update #1 (4/17/19): Apparently the Carbonized build of Snood I have on Mac OS 9 runs the CPU and fan at near 100% in Leopard too? Weird. It seems that Mac OS 9 really likes maintaining the CPU at 100% in general after testing Stuffit extracting on the SSD, Black Shades, Maelstrom (the GPL'd PPC version), and SimCity 2000 for a while. No shutting down issues yet however, though I wish this can truly stay quiet on OS 9.

Update #2 (4/18/19): My re-pasted mini G4 finally auto-slept from the heat as I was downloading (via Leopard-WebKit) and extracting (via The Unarchiver) a few files on Leopard. For whatever reason the fan turned itself up for a bit while I left the mini to idle after waking up again. It took about an hour for my mini to reach to this point, by the way.

[Ninester]

My 1.5 mini spins right up when pushed with games. Five rubber stick on feet raise the bottom panel 3/8" off desk.  Big difference as, before,  the desktop was very warm after 2 hours of Descent 3, now only warm.  Mine has the ram and SSD upgrades with, somehow, losing a resistor for a speed bump...another rescue puppy from the bay. The fan noise from the mini gets totally drowned out when my QS DP-1Gz gets a full head of steam...

I had read that Jobs detested games on the early Macs.  Lol, someone may think of them as toys..

[FdB]

“Update #2 (4/18/19): My re-pasted mini G4 finally auto-slept
from the heat as I was downloading (via Leopard-WebKit)
& extracting (via The Unarchiver) a few files on Leopard.”

[One of these days… I’ll get around to trying Leopard-WebKit.]

Been informed on more than one occasion that the full cooling effects of
replacing paste takes time b4 fully-realized. (Break-in or burn-in period?)
This HOT mini has me wondering & I’d like to have a close-up look inside
or... actually get my hands on it. (Apple Hardware Test?)
Still, some-thing is amiss?

Ninester reports his overclocked(?) mini gits hot, with no shutdowns.
Methinks mailcty’s HOT mini might have other problems/causes…
as no one else here has reported such prollums?

“had read that Jobs detested games on the early Macs.”
Alas, poor Steve… "we knew ye well.” (Long live The Woz!)

[mailcty]

Just added four 7/8" rubber feet to each corners of my mini G4's bottom pad, and while the bottom seems to actually feel cooler than before I'm still getting the auto-sleep/shutdown issues, particularly when attempting to extract 400MB+ Stuffit files on both Mac OS X Leopard and OS 9.2.2, with the CPU maxing out at 100% according to Leopard's Activity Monitor. About to run the Apple Hardware Test on my machine in a bit so I'll be sure to leave another update on this post.

Update #3 (4/20/19): Managed to burn a disc of the Apple Service Diagnostic which includes support for the late 2005 mini G4, and while a single ASD test set completed as Passed and the log reports an Error Count of 0, which should mean my mini G4 is fine, it still turned itself off ater about 22 minutes of being left on. I wish I can save the log file but this is just weird now. Perhaps I'll need to open it up again for a close look for anything I've done wrong physically, but for now I'll play the waiting game.

[Ninester]

I posted the Mini service source PDF.  It recommends changing out the ATI Sil-pad when motherboard removed.  Something to try for people having overheating issues. Found one source of official sil-pads but of course, are not cheap.  Looking for a sheet of the correct thickness.

I'll measure mine which is now in pieces..it died, best guess is the PMU won't reset or dead.  When doing research, I found reports of G4 mini's, powerbooks and intel mini with same problem that was fixed with a motherboard change out.  No one mentioned "OC" as in mine

My next mini gets the full treatment..if I can keep it from looking in the little box, now on the floor...

[mailcty]

I posted the Mini service source PDF.  It recommends changing out the ATI Sil-pad when motherboard removed.  Something to try for people having overheating issues. Found one source of official sil-pads but of course, are not cheap.  Looking for a sheet of the correct thickness.

Any updates on where to find a replacement sil-pad? I'm convinced that this is my only issue with the Mac mini and am eager to fix this.

[FdB]

PM Ninester directly...

Found one source of official sil-pads but of course, are not cheap.

[Ninester]

I'll post these here for any others looking.  I used the 1mm sheet and cut to fit...

https://www.amazon.com/gp/product/B00UYTTXSM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

[Roman78]

Is there any software for reading the CPU temperature or other sensors? I noticed mine mini blowing very hot air out the back while not doing much on it. I have a 1.42@1.5. It is standing on top of a Core2Duo MacMini 1.1. The intel one is much cooler. I am running MacOS 9.2.2 on the G4 and OSX 10.4.11 on the Intel.

[Ninester]

Nope, no sensors other than what you might read from the HD.  I lost my 1.57 OC mini, so just replaced MB with another 1.42. The old board only lit up when playing 3D games like Descent 3, the new board only runs luke warm with full paste and pad with stock clocks. The old board did not get a repaste.. being lazy but never a shutdown or graphic glitches.

I do have a Fluke thermistor probe but unless we all have something alike to share temperatures, while doing same benchmark, not much use?  OC again, in future, when workbench clear...

FdB, I did switch from a  MS mouse to a noname mouse. No lockups at full boot..yet.  Found other posts blaming their MS mouse...

[Roman78]

Strange, there are 2 or 3 sensors in that machine, but no software to read the information... hmmpppff...

Strangely i have a 1.42 Ghz Mini, but on the CPU is printed 1500. See Picture.

[mailcty]

Strange, there are 2 or 3 sensors in that machine, but no software to read the information... hmmpppff...

Apparently the Apple Service Diagnostic disc for the Mac mini G4 has the ability to either turn off or max out the machine's fans. Either its tricking the sensors at a very low level or its just merely switching them.

In regards to my 1.5GHz Mac mini G4, I've determined that it simply runs hot and just needs more time to really break its cooling in or it has some fault in the logic board. I went ahead with Ninester's way of replacing the ATI thermal pad and made sure nothing was obviously wrong with my machine before and after. Behavior is still the same, though the more I look into I realize that its dependent on the app/game's resource usage as would be expected, particularly since playing a little over 30 mins of Marble Blast Gold on Leopard doesn't end up forcing the mini to sleep, yet running Snood for 20 minutes on both Leopard and OS 9.2.2 and it'll (attempt in 9.2.2) sleep due to it using 100% of the CPU for whatever reason. My mini does get pretty warm though performance otherwise seems decent after repasting the CPU and replacing the GPU thermal pad.

Even though it seems I've hit a roadblock here I'd still like to thank FdB and Ninester for the help on my Mac mini G4. I'm convinced that repasting and getting a new thermal pad will help in the long term, even if I ultimately do replace my mini's logic board.

[Ninester]

Strange, there are 2 or 3 sensors in that machine, but no software to read the information... hmmpppff...

Strangely i have a 1.42 Ghz Mini, but on the CPU is printed 1500. See Picture.

Looks like mine!  I read your other post on this cpu. Someone said that Apple cheaped out on the mini but you can read temps on the G4 powerbook IIR.  My son's white intel macbook reports so many temp reading you get nauseated!

[Ninester]

Even though it seems I've hit a roadblock here I'd still like to thank FdB and Ninester for the help on my Mac mini G4. I'm convinced that repasting and getting a new thermal pad will help in the long term, even if I ultimately do replace my mini's logic board.

You plastic CPU stays are secure with the heat sink down flat?  I have not seen a 1.5 heat sink but curious if same size as the 1.42 and 1.25?

[mailcty]

You plastic CPU stays are secure with the heat sink down flat?  I have not seen a 1.5 heat sink but curious if same size as the 1.42 and 1.25?

The CPU heatsink is as fastened as it should be. I figured the image is too large to be on this post, and sorry for the low quality as its sourced from a video recording of me going through the thermal pad replacement process.

[Ninester]

You plastic CPU stays are secure with the heat sink down flat?  I have not seen a 1.5 heat sink but curious if same size as the 1.42 and 1.25?

The CPU heatsink is as fastened as it should be. I figured the image is too large to be on this post, and sorry for the low quality as its sourced from a video recording of me going through the thermal pad replacement process.

That should be your heatsink on ppg. 52 in the mini service now that I compared to your pic. Definitely a difference.  I had posted pictures of my rescue QS CPU's way back. They were stir fried but still ticking.  Hopefully someone with a true 1.5 will chime in for any like experiences?

[Ninester]

Went ahead and bumped the 1.42 to 1.5 today.  Maybe 1.57 in the future. No heating issues with 3D games in 9.2 or running Tiger version of chess.

I can only add that Tiger and 9.2 were clean installs...

Also...using a temp probe in the right side of exhaust vents; when temperatures ramp up to 124F, the fan begins to ramp up to medium(?) then temps back down to 117F depending on load. When all is at idle, maybe 102F with fan very slow.

[Roman78]

I made a picture while doing some CPU-Benchmarks. Im gonna make some when doing more work on it, or while playing games.##

[Ninester]

I made a picture while doing some CPU-Benchmarks. Im gonna make some when doing more work on it, or while playing games.##

This could be useful if person(s) having temp issues could also have the means to post readings...so trivial on later machines, no?

[Roman78]

Just used an old early 2000 CaseMod display with 3 temperature sensors and connected those to the Mini. One directly into the CPU Cooler, 2nd one on the bottom plate near GPU and one near the fan intake (ambient temperature). In my quick test i noticed the CPU is not the hottest in normal operation. The bottom plate and the ambient temperature reached 40°C in a couple of minutes.

So the HDD, GPU and Chipset may be causing the heat. Maybe an SSD upgrade could reduce the temp a little. Removing the bottom rubber and install some bigger plate could also be an option, an ugly one indeed.

When i was modding my MacMini 1.1 i came with the idea to use the Alu frame as Cooler, but faild to get that done.

[Ninester]

Just used an old early 2000 CaseMod display with 3 temperature sensors and connected those to the Mini. One directly into the CPU Cooler, 2nd one on the bottom plate near GPU and one near the fan intake (ambient temperature). In my quick test i noticed the CPU is not the hottest in normal operation. The bottom plate and the ambient temperature reached 40°C in a couple of minutes.

So the HDD, GPU and Chipset may be causing the heat. Maybe an SSD upgrade could reduce the temp a little. Removing the bottom rubber and install some bigger plate could also be an option, an ugly one indeed.

When i was modding my MacMini 1.1 i came with the idea to use the Alu frame as Cooler, but faild to get that done.

Nice probe work, lol.  That poor mini might be a bit sore...I had thought of getting one similar for my gaming box but no heat issues with old i5 and GTX 970.

I have SSD in the Mini...they get warm when worked but nothing like my 3.5 spinners!

Thinking about what you found with bottom plate temps... I tried out this: Laptop Cooler -  https://www.amazon.com/Belkin-CoolSpot-USB-Powered-Cooling-F5L055btBLK/dp/B00GLBI2IY/ref=pd_rhf_dp_s_cr_simh_0_8?_encoding=UTF8&pd_rd_i=B00GLBI2IY&pd_rd_r=c7bd6d34-434a-4985-a9be-5e3b7598ec3a&pd_rd_w=A3LYb&pd_rd_wg=GMOzr&pf_rd_p=67aa5820-8762-4202-90ba-881bb99c913c&pf_rd_r=HRYPBYD0GQPPY2B8WAC3&psc=1&refRID=HRYPBYD0GQPPY2B8WAC3

Wow, bottom plate cool to touch with air inside vent at 44 C after 1 hour of Quake 2 demo repeating for an hour. Ambient at 33 C with fan running medium?  Fan speed based on sound of full on speed with last dead mini. I have errands so will let the demo continue to repeat to heat soak the mini..

No temp changes but now finding fan speed may be sensed off the bottom plate, not the CPU.  Turned off the laptop cooler fan, bottom plate heats up, vent temp drops 2 C, faster running fan? I cannot hear or feel any fan speed changes but curious just the same. The fan is three wire so will check out the old fan header when time permits.