View Full Version : 12" PB G4, scorching!

Jun 10, 2011, 01:44 AM
I'm beginning to love my new 12", but I'm not quite there yet. It's still a little dirty from the previous owner, it stinks, (gotta do a teardown and rebuild, cleaning all the way:D) and it's hot as all hell!

The heat in palmrest above the hard drive makes it unpleasant to use. Is it because the HD is so old?

Will a newer hard drive operate cooler?....or is this just the nature of the beast? A small SSD would suit me fine, but it doesn't appear that IDE SSDs exist. Correct me if I'm wrong - I'll look into it if so.

Thanks for any insight.

Jun 10, 2011, 01:28 PM
My iBook G3 doe the same, I think they all get heated to a certain point. Mine gets hot after about 2 or 3 hours of use. As you said, its the nature of the wonderful PowerPC :D :cool:

Jun 10, 2011, 03:28 PM
A small SSD would suit me fine, but it doesn't appear that IDE SSDs exist.

They do exist. OWC sells them as Legacy SSD. Other way would be an Intel 1.8" SSD with mSATA->PATA adapter (there's one that will fit).
Other than OWC PATA SSDs are based on s****y JMicron controller, but they're cheap.
I have 32GB Transcend one in my Clamshell and it's way faster than original 4200 rpm was. Even with this crappy SSD machine got new breath and it runs 10.4.11 very nice (as for Clamshell OFC). But all I do with it is iTunes and light web browsing.

Jun 10, 2011, 04:22 PM
Ooh! I may consider the 40gig. Thanks for the tip!

Jun 12, 2011, 11:26 PM

As some of you may notice, I tear things apart quite frequently.

I removed the top cover on the PB today and did a thorough spring cleaning. The fan had a good amount of dust in the housing. The fan is already a 40mm if I had to guess, so it struggles by design to keep this thing cool.

The CPU had godawful amounts of crusty, hardened thermal paste applied to it. There was also a thermal pad for the CPU that was placed around the core, but not over it. It seems they tried to use both thermal paste and a thermal pad for some reason, even though the pad doesn't come in contact with anything.

I also rubbed off the GPU and huge "Agere" chip using alcohol, that the heatsink also cooled using soft blue thermal pads. Arctic Silver 5 was applied to the CPU core, and the rest is history.

Before doing this, the laptop would almost always have the fan running constantly. Battery life sucked, and it was extremely hot to the touch as you all know from my first post.

I think the CPU was honestly heating up the top cover to the point where the palmrests even got toasty! Now, I'm writing this and the CPU is at 48C, and the GPU is at 52C. If I remember correctly, the CPU and GPU were both about 10C hotter, and after playing a game, would be near 80C.

Very happy with this laptop now. It's much sturdier after the rebuild, and may hold off on the SSD too. Hard to justify it anyway on a computer that costs just as much as the drive itself :p

If anyone has questions about this process, feel free to ask away.

Jun 13, 2011, 01:00 AM
I'm pretty sure pads come stock on these. Do they ever wear out? I was under the impression that you couldn't just clean the pad off and use paste because the heat sink was designed with the thickness of the pad in mind such that, if it was missing, it wouldn't make good contact with the die.

I would like to know about this because I've got some Arctic 5 and if there's something that can be done to reduce my temperatures a little bit, that would be great. I hate the fan. It's the only noise on the machine now.

I recommend the SSD. I use the 240GB one from OWC.

Jun 13, 2011, 01:50 AM
To clarify, I dabbed the pads with rubbing alcohol, they had a greasy film on them. The pads were adhered to the heatsink assembly.

The only chip you can apply thermal grease to is the CPU, it is the only machined die on the computer. The GPU and Agere (wish I knew what this huge chip was) chip are black chips, nonmetallic, and cooled through the pads.

I highly recommend going in and cleaning up the CPU. You'll end up chipping off huge pieces of hardened thermal grease, and that feels good.

Did you notice an increase in battery life with the OWC SSD?

Jun 13, 2011, 09:25 AM
About 15 minutes increase in battery life. The idle watt consumption is quite low, but active is right there with most spindle drives. The biggest benefit is lack of noise and speed.

There might be more of an increase with the smaller drives, because there are fewer memory chips to keep awake. Maybe less heat, too.

Jun 13, 2011, 03:11 PM
I removed the pads completely on my powerbook, when i replaced the logicboard (lower ram slot failure) a year ago. On the large chips (memory controller, i think, and gpu) i applied 5 small dots of thermal paste on each. No problems so far with temperaures, even running hours of full load. The book gets hot though, but never goes above 63C/ 145F. Idle temps are 45 C/113F, i think its normal then, even without the pads...

Jun 13, 2011, 06:15 PM
Is yours a 12"? If not, is the heatsink basically the same across the range? (15" 17")

I was under the impression that the heatsink would not make firm contact with the chips unless the pad was there to bridge the gap. If I can use paste and still have it work, I'd love to go back in and do that.

Jun 13, 2011, 07:34 PM
My 12" PB G4 ALWAYS ran hot, especially the left palm rest...I believe that's where the HDD is.

Jun 13, 2011, 09:47 PM

I think we can attribute that to the poor heatsink design. There aren't many fins, and not a lot of space for the air to be pulled through it. All the heat just rises through the top case and into your hands!

There is actually a thermal pad on the top case that is right above the top part of the heatsink. My guess is that Apple designed it to use the case of the computer as sort of an extended CPU heatsink, being that the whole thing is aluminum anyway.

Jun 14, 2011, 12:18 AM
You are right, i removed it on a 15", but i remember, i was worried that removing those pads on the 15" heatsink would leave a gap. I thought i try it out, and if the temps are too high, i put a small square copper plate between to bridge that gap. If the pad is in good shape, maybe its best to leave it like it is.

Jun 14, 2011, 04:47 AM
There is actually a thermal pad on the top case that is right above the top part of the heatsink. My guess is that Apple designed it to use the case of the computer as sort of an extended CPU heatsink, being that the whole thing is aluminum anyway.

True. That's how it is.
BTW, you can replace old thermal pads with 3M ones (http://www.arcticmod.com/computer-mod/3m-thermal-conducting-adhesive-pad-1-x-1.htm).