Thermal Optimization
of the nw8240

Overview

Please note that I'm not sure if opening up your laptop voids your warranty or not. Just a word to the weary.

In any case, the objectives of this task are to clean out the heat dissipation system on your laptop and also add some better thermal paste to the CPU, graphics chip, and another chipset I haven't identified yet. If you've never added Arctic Silver to a CPU before, it helps to look at the tutorial on their site. Let us review the materials and equipment.

Materials and Equipment

• HP Compaq nw8240 (nw8440 should work as well)
• Torx T9 screwdriver
• small Phillips screwdriver
• medium sized Phillips
• small, thin flathead screwdriver
• small tray to hold screws (I used the lid of my electrical tape roll)
• lint-free cloth, such as lens cleaning cloth or coffee filters
• Isopropyl (rubbing) alcohol, preferrably >90% purity, but 70% worked for me OR
• ArctiClean (I didn't need it in this case)
• Arctic Silver 5 or similar
• air compressor with blowgun (optional)

How-to

	On the underside of the laptop there is a little cover, near the middle. By it you will see two little keyboard symbols with arrows pointing to two screws. You'll want to use the Torx T9 screwdriver to take those out. Be sure to put them someplace where they won't get lost.
Now flip the laptop over and open it up. On the keyboard there are four tabs on the top that you'll have to slide down with your fingernails or that small flathead screwdriver. I have no fingernails, so I used the screwdriver.
	This is what it should look like once you've taken the keyboard up. Flip the keyboard down over the trackpad and you'll have access to the aluminum cover. I've highlighted the screws you'll need to take out or loosen. The cover on this model has instructions saying to remove certain screws in order, so follow that if that's your case. Some of the screws are spring-loaded and permanently fixed to the cover, so all you'll have to do is loosen them.
Before lifting the cover up, you'll have to disconnect the fan plug. It's highlighted in the picture. You should be able to pry it off with that small flathead screwdriver - just be sure you don't sever any wires or poke through to the motherboard. That would be a very bad thing.
	Now wedge that flathead under the right side of the cover and it should pop up. Just be gentle and it'll come up with no problem. You might have to finesse it out of the laptop as it has a tab on the left side that sticks under the casing. Once it's off, use the blowgun or your mouth to blow the dust off the fan while trying not to get any dust on the foamy-looking pads on the underside.
This is what you should see with the aluminum cover off. The video chip and another chip that I can't identify are laid bare, along with the CPU and it's heatsink. The yellow circles highlight the screws to take off the CPU heatsink. The screws are fixed to the heatsink, so all you need to do is loosen them. With the screws loosened, slide the heatsink out of the case. It might be a bit suctioned-on to the CPU because of the existing thermal paste, but it will come off pretty easily. With it out, take a look at it. It's got a thermal pipe and the copper heatspreader. Use the blowgun or your mouth to blow the dust out of the fins. You can blow the dust off of the vent holes in the case as well.
	See that grey gunk on the CPU? That's thermal paste. You have to clean it off. Get out the Isopropyl (rubbing) alcohol and your lint-free cloth. Get a bit of the cloth soaked and proceed to wipe off the CPU. You want to get every last bit of it off. Do the same with the bottom of the CPU heatsink and make sure the video chipset and that other chip are clean as well.
You'll know the CPU is clean when you can see light reflected clearly. Heck, I could see my reflection when I did it. Double-check that the bottom of the CPU heatsink, video chipset, and the other chipset are completely clean and dust-free too - the next step is adding thermal paste.
	Again, if you've never added Arctic Silver to a CPU before, it helps to look at the tutorial on their site. Place a small dab of paste in the middle of the CPU. Do not spread it around - the pressure from the heat sink will do that. You'll want to use an amount about the size of half a grain of rice. Put about the same amount on the video chip and that other chipset.

Now it's time to put everything back together.

The CPU heatsink is first. Slide it back into where it goes, making sure to keep it from sliding against the CPU when you do this. We don't want the thermal paste to get smeared. Once the heatsink is situated correctly, start screwing the screws back it. Do it in the same fashion you would screw the lugnuts on a car tire. Get two opposite corners most of the way down, then to the others. Don't fully tighten one screw and then move on to the next - the objective is to get the heatsink to seat evenly, thereby spreading a uniform layer of Arctic Silver between the CPU and the heatsink.

With the CPU heatsink completely tightened down (don't overtorque it), the aluminum cover needs to go back on. Slide the tab back under the case (it should fit between the plastic of the case and the top of the heatsink fins). Press the cover down to its original position and put the screws back in the opposite order than it told you to take them off. You want them tightened down enough so that solid pressure exists between the two chips and the cover. Make sure you replace all the screws - refer back to the screw diagram to make sure you get them all.

Be sure to reconnect the fan plug as well. It should slip back in with no problem.

Now flip the keyboard back in, being sure to fit the tabs on the bottom if it into the case. Slide the tabs on top back to their original position to lock the keyboard in place. Then close the lid, flip it over, and replace the two Torx-type screws on the bottom. Done.

Results

Due to the unique shape and sizes of the particles in Arctic Silver 5's conductive matrix, it will take a up to 200 hours and several thermal cycles to achieve maximum particle to particle thermal conduction and for the heatsink to CPU interface to reach maximum conductivity. (This period will be longer in a system without a fan on the heatsink or with a low speed fan on the heatsink.) On systems measuring actual internal core temperatures via the CPU's internal diode, the measured temperature will often drop 2C to 5C over this "break-in" period. This break-in will occur during the normal use of the computer as long as the computer is turned off from time to time and the interface is allowed to cool to room temperature. Once the break-in is complete, the computer can be left on if desired.

Temperatures before Arctic Silver 5