Using VapoChill with Socket 478
Using a VapoChill with a Socket A board is a different kettle of fish to a Pentium 4 based Socket 478 motherboard. While the VapoChill head is designed to clamp on to the socket lugs on a Socket A board, the size of the socket on S478 is too small for that to happen.Asetek came up with a quite ingenious method of mounting the VapoChill to a Socket 478 board, so I'll cover that here.
As before with the Socket A mounting, you want to read the manual thoroughly a couple of times to get an idea of what you're about to do. It's no more difficult than attaching an air cooler, just more involved since there are more steps and you need to take a little more care.
To start with, you want your bare motherboard out of the case and free of any motherboard tray, so that you can remove the existing heatsink retention mechanism. The mechanism is still used to attach the VapoChill, but it needs beefing up first. Pushing out the pins that hold the bracket into the motherboard sets it free. With the test motherboard, an EPoX 4PDA2+, the mechanism is also held in place by a set of expanding black pins that hook the legs of the mechanism when pushed through to the back side of the board. Thankfully, and needfully, they could also be removed.
With it free of the motherboard, the first piece of insulation foam is placed underneath the retention mechanism. The idea is to create a closed cell for the CPU to sit in, free of air and moisture, the bane of any subzero cooling solution. So the bottom layer of foam forms the bottom of that closed cell, allowing no air to get in under the retention mechanism. Then a pair of equal length steel bars are pushed through the holes normally used to secure an air cooler to the mechanism. These are what the VapoChill head will screw into when finally mounted. They are also the hardest parts of the socket mounting assembly to put together. To stop the bars sliding free of the retention mechanism, a pair of locking disks are provided for the end of each bar, to hold it in place. I had real trouble getting the locking disks on the ends of the bars, once slid through and in place, they are very hard to push on. By design, there's no way those bars can be allowed to wriggle free, so the locking disks are absolutely essential, but they did conspire to give me incredibly sore finger tips by the time I'd got them stuck on.
Now you've got the bars in the mech and the first piece of foam tentatively in place, you then screw the mechanism to the motherboard. Using the supplied screws and nylon washers, it's much like attaching something like a Swiftech MCX478 heatsink. The screws and washers are vital in holding the mounting mechanism to the board as tightly as possible, giving the VapoChill head something strong to hang on to as it cools the CPU.
With the mechanism attached the motherboard, all I had to do was use a small pair of tweezers to slightly adjust the foam, so that manipulating the lever for the socket was possible, since it slightly covered it at first. The manual mentions that you might need to do just that.
Next up, similar to using VapoChill with Socket A, you want to prepare the socket with the supplied thermal compound. The idea again is to fill all the socket holes with thermal compound, along with the inside area of the socket, so that any air that decides to creep in is met with an impenetrable barrier before getting anywhere near your precious CPU pins. Since the socket is much smaller than Socket A, it was an easier job this time around and takes much less time. Be careful to completely fill all the holes, don't be tempted to leave the final few that you can't seem to fill properly. Make sure you get them all.
Placing the supplied tiny square of neoprene foam into the compound coated middle of the socket is next, then you can prepare the CPU. Unlike with Socket A, the back side of a Pentium 4 has surface mount components, so you give them a thorough coating too. As thick as you like at this point, don't skimp on it.
Using your finger, push down on the heatspreader as you hold the CPU into the socket. There's resistance from the thermal compound that wants to push the CPU back out of the socket due to pressure, but a steady finger will hold it flat to the socket so you can close the lever. A quick wipe of the heatspreader with a soft cloth or some toilet roll to remove any natural oils that form finger prints and you can leave the CPU in the socket, naked, as you insulate the back of the motherboard.
You get two sets of pin heaters this time, unlike the single one with a Socket A kit. It's an actual Socket A pin heater that goes on the back of the motherboard, around the pin area, to keep them warm while you chill the CPU. Keeping them warm stops the VapoChill dropping the temperature of the socket area down below the dew point of the air, pulling the moisture out of the air and onto the pins. It's a sticky pad like before, so peel it off and place on the back of the motherboard on the right spot. Now use the largest piece of adhesive neoprene foam to cover that pin heater and stop air getting anywhere near those pins you are keeping warm.
Now you can mount the motherboard into the case, onto the removable motherboard tray. It's the same excellent push through mounts that I mention in the original article, one of the best features of the whole package. With the motherboard in place, you want to adjust the length of the available hose on the VapoChill head, so that it rests nicely over the socket so you can mount it shortly. You do this with the VapoChill case laid on its side, CPU in the socket. A little thermal paste on top of the CPU heatspreader lets you know you've got the alignment right and the evaporator will be clamped to the top of the CPU.
Some final socket preparation now, with the last piece of the neoprene sandwich that you tease into the top of the mounting mechanism, fitting it around the CPU socket. The other pin heater goes on top, the one with the smaller cutout that's the correct size for the Pentium 4 processor. That's it, all ready to mount the VapoChill once you've covered the CPU with a thin layer of thermal compound.
With the unit still on its side, the VapoChill head lined up nicely and resting nicely above the socket on its own tension and the screws in the middle of the two available holes on the head, you can start screwing it in.
The bars prepared earlier have screw taps that you screw the VapoChill head to. It's this that mounts the head to the CPU. Just like the Socket A version, you screw a little at a time on each side, alternating between the two, gently lowering the evaporator head on to the heatspreader. The evaporator head can move a little here, so use your spare hand, or a friend giving you some help, to keep it steady, dead centre over the top of the processor. It's easy to do solo however, moreso than the Socket A solution, since movement of the head can't cause the head to jump off the socket lug mounts, because we aren't using those with Socket 478.
Screw down until you feel the tension in the screws increase. Once that happens, a couple more turns will see you secure. You'll notice the top of the neoprene sandwich deform, due to compression of the evaporator head, but that's perfectly normal. The clamshell neoprene gasket on the evaporator head conspires with your neoprene sandwich to create an airtight seal around the CPU, just what's needed.
Done, and easier than with Socket A.
All you need to do now is give it a cursory glance over to make sure it's all set, attach the pin heaters to the two pin heater headers on the ChillControl, stand the case normally on its base and install the PSU, just like with Socket A.
Now we can switch it on and use the system. I won't cover setting up the ChillControl again, other than to say a pin heater load of 100% is recommended for Pentium 4's by Asetek, rather than the 60% load used with Socket A (normally). Benchmarks and system setup now, to see how the XE cools our monster processor.
