Thermal Paste and Thermal Pads

Hallucinogen

Okie dokie. I may or may not be having to re-seat my CPU and GPU, and I have a few questions I hope can be answered. The CPU has quite a number of exposed pins around the die, so I'm thinking ceramic paste is my best bet to avoid the chance of connections being made if it spreads enough to leech onto them, though it shouldn't if i do a proper job.

My main concern, however, is that there's a chip, not the CPU/GPU, that has a thermal pad on it. I'm wondering if I should replace it with a new one, replace it with paste, or leave it as is. I'm not sure if it's wax or graphite or what, but I have a feeling it's a wax-based pad. I suppose I should find out in order for you guys to provide any useful info. Problem is I'm on the computer that the chips are in.

All three have to be re-seated because they're all attached directly to the motherboard. The reason they need to be reseated is because the paste was applied kind of sloppily by the factory, and it runs hotter than I bet I can get it running with better paste that's been applied with more care. Even 2-3 degrees to me is worth it when I routinely hit 62-64 degrees(I do a lot of video and graphic work).

Yes i know I could end up with the opposite result, but that's only if I do something stupid. I'm going to do a test application on another system I can afford to ruin.

Dixon

First I would go with a paste, the pads are a lot easier but from my experience they don't do as well, also what processor ar you using. For some CPU's 62-64 isn't so bad, I once had a p4 @ 3.2ghz that would run like 75 under load. Something else to check out would be to change the stock cooler if you using one. You can get like a $40 heatsink/fan that can make dramatic changes.
I'm not sure if you have a motherboard that supports temp gauging on more then just the CPU, I'm not to sure what the other things are that need changing, think you could supply your mobo model number and maybe a pic with the things you think need changing, just like google an image and then paint edit it with circles around the stuff. Like is it your northbridge or something?
I would prob only change the CPU paste if had to as well, what sort of case are you using? You'll want to check the ambient motherboard temperature to if your motherboard supports that, you should be able to check something like that with a program called Rivatuner.

Hallucinogen

It's a laptop, so a better heatsink isn't an option, and it's a powerbook G4. The only temp sensor that's any use is on the CPU, there is no sensor for the GPU, the rest are not important(like battery/PS etc.)

Here's a photo from ifixit.com, it's a pretty bad job of application, you can see the paste is contacting quite a few exposed pins as well, and I'm betting mine's the same.



The chip that had the thermal pad is between the CPU and GPU, which have paste. I don't know what it's purpose is exactly. It must not get that hot though, hence why Apple chose to use a pad.

Part of the reason for re-applying the paste is because there's something I want to fix that requires the removal of the logicboard/motherboard, so it's not really a choice.

I still have Applecare, so I don't think I'll be doing this until it runs out, just in case something else goes belly-up. The thing I'm fixing isn't worth taking in to have it repaired, in fact it was caused by the guy replacing my defective display. I'd rather he not screw up something more important. Now, you might ask, why bother to risk wrecking the CPU over something not worth taking in to be repaired? For fun, because of a perhaps slight temp improvement, to fix the part that's broken, and to learn. I intend to build my own PC in the next little while and ditch Apple, so experience won't hurt.

Dixon

Oh ok lol, it's a laptop I thought we were talking about a desktop. In that picture that is a pretty shitty job. What were the temps at like before that dude messed with your lcd?

I say go for it, I mean after the apple care (warranty i assume) see what sort of difference it makes, what sort of paste will you be using?

Hallucinogen

The temperature hovers around 45-48 C during normal use. As soon as I do anything with video, including just watching a movie(watching DVDs seems to not cause such a hit), or photoshop/Illustrator, it rockets to 60-64 C, I've even hit 68 on occasion. Apparently the threshold for this chip before damage and automatic shutdown occurs is above 70C. I've done the best I can as far as external heat conduction/convection, the PB is on raised rubber feet(thicker than the ones it has attached) on a large aluminum platform with fans built into it, it drops the temp by maybe 1C under minimal load, and under stress it does nothing. If I put high-speed fans directly on top of the top panel right up to the display where the heat exhaust vent is, I get a 4C temp decrease, but its not very convenient, nor portable.

The temp doesn't seem to have changed much since the repair, but I doubt the repair guy put much care into the application of the new paste. Hell, I wouldn't be surprised if he just slapped the chips back down onto the old paste.

As for the paste, I'll probably use Arctic Silver's Céramique, seeing as there's all those exposed pins near the die on both the CPU and GPU.