Make S’mores Inside Your Desktop PC

Your desktop PC’s CPU can run pretty hot. That’s why you have a heat sink, a few fans, maybe even a liquid cooling setup. But why not use that heat for something? Something like making delicious s’mores.

Disclaimer: We’re showing you how to cook in your PC by running a CPU without any cooling system in place. Try this yourself, and you risk frying your CPU and melting sticky food items near important electrical components. You have been warned.

The Ingredients

A traditional s’more consists of marshmallows and milk chocolate sandwiched between two graham crackers. In the interests of speed, precision, and covering my butt for this experiment, I purchased a bag of miniature marshmallows, instead of their full-size cousins, because they’re easy to cook through. Grab some aluminum foil for a makeshift pan, and you’re ready to go on the ingredients-and-cookware side.

For the desktop, I used an old HP system that was lying around in the PCWorld Labs. The experiment calls for running a CPU with no cooling elements attached to it whatsoever, which is a great way to put your chip at risk of frying or, at the very least, having a shorter lifespan. In addition, the experiment involves melting food items near important electrical components, and using electrically conductive aluminum foil as a cooking pan on the CPU. One short and the motherboard could bite the dust.

The Trial

Before going for the full food-on-CPU experiment, I decided to conduct a test trial on my system’s exposed Southbridge chip, the IXP 400. Though I couldn’t identify a temperature reading for the chip, I did confirm that it got too hot to touch for longer than a second or two once the system had been idling for a while. Ouch. The chip seemed to be the perfect place to test out my aluminum foil “pan,” which I would use as both a heating tray and a protective device to keep the food away from important chips.

I took a small piece of aluminum foil and made a tiny cookie-pan-style boat to hold my foodstuffs, curving up the edges of the squared piece. I smoothed the bottom of the pan to make it as flat as possible, for maximum contact–the more foil touching the hot chip, the better. I also took special care to avoid making the pan too large: Too much overhang, and it might conduct current between two motherboard leads. Brrzap!

Unfortunately, careful or not, either I left a wee bit too much overhang on the foil pan or I jostled the foil at a critical moment, because the HP system soon fizzled to a complete stop. This time I decided to set the foil on top of the Southbridge chip before turning the power on. When the system was up and running again, I gave a quick sigh of relief at still having a functioning motherboard and carried forward with the cooking. For the next 15 minutes!

The results? No perceptible change. The marshmallows didn’t melt and didn’t even seem to get very gooey. I might just as well have set the sugary cylinders on a room-temperature tabletop as on a hot chip. So I decided to disconnect the heatsink and the fan from the system’s Athlon 64 3500+ processor to remove their baleful moderating influence.

The Test

Once the fan and heatsink were out of the way, I figured that I might as well unplug the entire contraption from the motherboard itself–it was a bit iof an obstruction, and I didn’t need cool air blowing over my snack. So I cleaned off the filthy, thermal-paste-covered processor with a two-step ArtiClean solution from Arctic Silver (see “How to Clean Your PC, Inside and Out” for additional internal system cleaning tips), and then I carefully mounted my little foil pan, added two marshmallows, and fired up the system.

After about 5 seconds, my test computer sensed that the CPU fan wasn’t connected and, to spare the system from exploding in a fiery rage, automatically shut down the desktop. It looked as though I was going to have to plug the case fan in after all and then nullify its cooling effects by jamming a screwdriver between its blades (don’t try this at home, kids).

I fired up the HP system once again. This time it lasted about a minute before shutting off again–this time with an unpleasant beeping noise. Most CPUs run too darn hot, and in the absence of a cooling system the CPU will quickly overheat to an unsafe level that forces the entire system to shut down before the CPU can reach a PC-damaging temperature.

To solve this problem, I reapplied the CPU’s cooler and heatsink, booted into Windows, and grabbed a freeware app called RightMark CPU Clock Utility. This app is allows you to make on-the-fly adjustments to a processor’s multiplier and voltage within Windows itself, and it comes with a great set of monitoring tools that provide real-time readouts of a chip’s particular temperature.

So if you think of my CPU as a stovetop burner, RightMark CPU Clock Utility was my brand-new temperature knob. (Readers who are willing to put their Windows 7 PC at risk for the sake of s’mores might use ALCPU’s Core Temp instead.)

I cranked down the voltage and multiplier of my AMD chip until I reached a specific setting (1.050 volts) and a multiplier that generated a 1.0GHz clock speed, yielding a stable CPU temperature of around 95 degrees. That’s a higher temperature than I’d want my CPU to run at for standard desktop use, but a chef must do what a chef must do.

I let a miniature marshmallow sit on the makeshift pan for around 15 minutes at the stable CPU heat, and it gradually became far mushier and malleable than a standard, out-of-the-bag confection. Then I turned my attention to the chocolate, dropping a Hershey’s Mini bar directly onto the foil pan.

In a few minutes, I was cackling with glee. The chocolate responded to the heat from the a CPU’s heat far more thoroughly than the marshmallow had, in part because it was heavier and had more surface area in contact with the pan, but also because the melting point of chocolate is about 15 Fahrenheit degrees lower than the melting point of marshmallows: If you gently hold a marshmallow in your closed hand for 15 minutes, you’ll end up with a slightly warmed marshmallow; if you gently hold a chocolate bar in your closed hand for 15 minutes, you’ll have a serious chocolate mess (think of this phenomenon as illustrating the M&M rule).

For my final setup, I put a miniature chocolate bar on top of two miniature marshmallows. At its greater distance from the pan, the chocolate took about 10 minutes to heat up, but it eventually started running and dripping over the semisquishy marshmallows. Good enough for me!

I lifted chocolate-covered marshmallows out of the pan, set them down on a graham cracker, and topped off my creation with another graham cracker. The gooey s’more tasted pretty good–not campfire good, but not cold-ingredients-off-a-shelf lame, either.

The Culinary Conclusion

If you’d like to replicate my experiments in the kitchen of your computer, here are a few key tips: Make sure you have a solid contact between your heating pan (in my case, an aluminum foil holder) and the CPU to maximize the heat transfer between the two surfaces.Carefully watch your CPU’s temperature to ensure that it’s not marching into shutdown territory; you’ll probably have to underclock your chip to get it to work without a cooling system. Above all, pick ingredients that cook at relatively low temperatures–you’ll have a lot more success with scrambled eggs than with a steak. Be patient and don’t be afraid to think outside the box if your initial plans don’t work out. You can even try carefully cranking up the heat, but don’t say we didn’t warn you.