One reason why the Xbox 360 has so many problems is poor air circulation. When you open up an Xbox 360, you see 2 heat sinks and a white plastic "shroud" coordinating air flow.
What the Microsoft engineers seem to have forgotten is that air will travel in the path of least resistance. As a result, the heat sink on the left (for the GPU) receives a very small portion of the air flow to cool it off... this is why the GPU is where most problems occur on the Xbox 360.
To fix this, we're going to create a divider so that both heat sinks will receive equal air flow - greatly reducing the operating temperature of the GPU. I would highly recommend doing this to any 360 that is not under warranty, as it can prevent the RRoD.
First, download the PDF template for the divider.
Print it out on either plain computer paper or card stock (doesn't matter)
Use some duct tape and tape the back of the paper behind the design - this will give it some rigidity if using paper.
Now flip it back over and cut out the design!
This should be the result once you're done cutting.
Now make a small 2-piece wide sheet of duct tape - sticky side up and place your divider on top. We're doing this so that both sides are taped and we can still see the outline of the design.
Cut off the excess duct tape while following the design. Your divider should now be fairly rigid and fully covered in duct tape.
Now that the divider is complete, take the plastic shroud out of your Xbox and do a test fit.
Notice how the divider touches the motherboard, but does not obstruct anything around the heat sinks. There is a small black capacitor near your fan - just put the divider on the other side of it as pictured.
Place the shroud back onto the Xbox 360 to make sure everything fits and nothing is obstructed.
Pull the shroud and the divider off together, so that the position of the divider will be correct when you place it back on. Tape the divider to the shroud.
Now place the shroud back on your Xbox 360. Guide the divider to make sure it's in the proper position.
Reassemble your Xbox 360 and enjoy a cooler GPU!
Please note that using this template on cardboard is okay. Some people think cardboard will catch fire, but I've tested the flammability of the cardboard with my heat gun using temperatures far hotter than anything your Xbox will ever produce (800F). The worst it did was blacken it. Also, please be sure to keep your Xbox 360 in an open area with plenty of ventilation so this mod can do it's job!
Until next time...