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Can Someone Speculate Why SOME MBPs Are Cooler After Updates?

Why are some better and others (like mine) still very hot even after the same software and firmware updates?

Thanks ... Ken

MacBook Pro (s/N 8610; 2.16) 100Gig 5400, Mac OS X (10.4.6), Also own G5 Dual 2.5

Posted on Apr 14, 2006 7:41 PM

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104 replies

Apr 14, 2006 8:09 PM in response to vinbot

I have no whine just a VERY hot machine.

Some report that after the 10.4.6 update theirs was cooler and others got cooler after the FW update. And yet others report cooler machines after both updates only.

Are not the 0s and 1s the same in my machine (which remains uncomfortably hot) as those that got cooler. Especially if this is a SW issue.

Thanks ... Ken

Apr 15, 2006 8:09 AM in response to sgginc

Couple of things: (1) If the back of the MBP is elevated there seems to be better air flow, thereby enhancing the cooling effect of the fans, whereas when the MBP is on a desk, some heat may reflect back--essentially same issue with the Powerbook G4.

(2) More importantly, different heat performance likely have something to do with variations in build quality, let me explain. If you look at the Ifixit site, they have a great picture of the logic board and the CPU, GPU and chipset sitting all in a row along the back of the laptop. These chips are cooled by contact with a heat pipe and the heat flows along the pipe out to the fans and air duct. This allows the laptop to be thinner, but does not provide direct cooling on the chip.

Well, I recently opened my MBP down to the logic board to take a look at these chips and what did I find....**** poor application of the thermal compound. There appear to have been some heat damage in the surrounding silicone wafer as well (a bit of a bubbling up)

There was tons of excess compound leaking out aroung the silicone border of all three chips and very little on the chips themselves. So, and this is not for the faint of heart or those wishing to hold on to their warranties (and don't say I didn't warn you) I cleaned all the gunk off until I had the chips and surrounding surfaces completely clean and shiny (some recommend using some form of alcohol to clean off the chips, but I prefer not to use potentially caustic liquids near my MBP--besides, the stuff wipes off fairly easily). Then, I replaced the thermal compound with sparing quantities of Artic Silver 5. Indeed, if you look at the directions for AS5, a small drop is sufficient.

Since then , and its been only a couple of days, my MBP is very cool to the touch. The AS5 renders the heat transfer process between chip and heat pipe more efficient. Note, that it takes a couple of cycles for AS5 to reach full effectiveness. According to the instructions a cycle is heating the chip and AS5 to highest temperature from normal use, and cooling when the computer is turned off.

Disclaimer: As I hardly ever keep a computer for more than a year, I don't get Apple Care (yes, expensive hobby but ther are worse.) so I am not concerned about the warranty. If that's not your bag, don't do it.

Also, this will likely not be a problem with all MBPs, but more a quality control with some. On balance, I don't have the whine or any other issues others have identified and this was a minor fix.

Apr 15, 2006 9:21 AM in response to Jean-Cyril

Very nice AS5 ( I was thinking of doing this myself)

Question:

Is the heat sink adjustable? (Is the gap between the heat sink and cpu easily adjustable?)

It's not clear from the fixit site if you can self adjust this part ( I don't see were the heat sink height can be adjusted to allow for different thermal grease layer thickness as it looks like they used thermal pads which have a different clearance than the AS5 type grease.
Normally there are a set of screws that you adjust in a rotation pattern (like lug nuts on a car wheel)

Note: as this adventurous fellow has said you VOID your warranty if you do this.

Apr 15, 2006 9:30 AM in response to mac wison

Are you absolutely SURE you void your warranty by doing this? From my interpretation, it sounded like Apple's warranty was basically "If you open it up yourself, and break something, you're on your own. But if you don't break anything, we won't hate you for opening the case yourself."

Apple's warranty page: http://www.apple.com/legal/warranty/hardware.html

And the relevant portion...

"This warranty does not apply: ... (d) to damage caused by service (including upgrades and expansions) performed by anyone who is not a representative of Apple or an Apple Authorized Service Provider; (e) to a product or part that has been modified to significantly alter functionality or capability without the written permission of Apple;"

I don't think adding better thermal compound would count as "significantly altering functionality"...and it doesn't seem to say anything about "if you open your case, your warranty is void" like some other evil computer manufacturers...

Apr 15, 2006 9:32 AM in response to Jean-Cyril

Improving thermal conductivity between the source, primarily the CPU, ICH, MCH and GPU chips, and the external environment will make the outside of the case hotter, not cooler. If you actually succeeded in making your MacBook cooler, you've probably shortened its life by raising the temperature at the source of the heat, the semiconductor junctions in the key chips.

Randall Schulz

Apr 15, 2006 9:44 AM in response to Randall Schulz

I see what your saying but it's not all that clear.

If you improve contact area you improve the efficiency of the whole system including the fans.

The notoebook will OVERALL feel cooler (the bottom may be a little hotter -maybe) and it could greatly extend it's life span if the contact was poor to begin with.

As a matter of fact, if the contact is bad you could fry your notebook,( especially these ones)

But I think that it's safe to assume that the way these are put together there is probably a good contact since there's apparently no spacers to be adjusted.(in other woulds all most all of them are okay)

So unless yours is really to hot to touch, it's probably running normally; that is, very hot.

Apr 15, 2006 9:42 AM in response to Randall Schulz

I disagree. The reason heat is building up on the top of the laptop is because it was not being channeled along the pipes to the fan and out the back. Indeed, if your assessment was correct, then I would not have had the damage to the silicon that I witnessed. The heat has to go somewhere, and providing a more efficient pathway to the pipe means it goes out where it was designed to go.

I would agree that the bottom of your laptop would be warm, but not the top and at the temperatures that I experienced. I've built enough PCs and worked on enough laptops to know whereof I speak. As I said initially, this may not be the case with all the laptops with heat issues, but the evidence of sloppy application in mine was quite plain.

Apr 15, 2006 9:47 AM in response to mac wison

Mac,

You are absolutely correct. The bottom is warm but not HOT. The top is lukewarm and this is after the laptop has been running on my table top instead of my Ilap for three hours. Indeed, I can almost locate the heat pipe by running my hand under the laptop and feeling which part is warmer than the other. As I would expect, the leading edges of the fan exhaust seem warmest.

Apr 15, 2006 9:54 AM in response to mac wison

Mine was definitely abnormally hot. The most tight fitting laptop I ever had was the Sony Vaio 460, and this was definitely way hotter. What led me to think that I had a problem was when I was in my local Apple store a few days ago and I ran my hands on the top of the display models.

Again, given the placement of the heatpipe, the bottom of the laptop should be warm to hot. But heat at the top indicates leakage, because (1) the radiating part of the chip is pointing down, and (2) most of the space along the heatpipe is not touching the top of the laptop, there is empty air.

So, either the fans are underpowered for the heat pipe and don't move air quickly enough or the heat is escaping directly from the chips.

Of course, I need to put my money where my mouth is, and need to get an instrument to measure the heat.

Can Someone Speculate Why SOME MBPs Are Cooler After Updates?

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