Alienware X51 R2 Overheating, Huge framerate drops, Distorted audio

I have an Alienware X51 R2 with a 2GB GDDR5 NVIDIA GeForce GTX 670, an Intel Core i7-4770 and 16GB Dual Channel DDR3 RAM at 1600Mhz. I basically selected all of the most expensive options for this PC.

Using the latest nVidia drivers (both beta and non-beta), the GPU will overheat very quickly in most games, but not all of them. I can max out Lost Planet 3 and get 60 FPS for hours with no incident, but if I try to max out Lost Planet 2, the GPU will overheat.

In Saints Row 3, nVidia Experience recommends I max out all the settings. For a minute or two, this will run 60 FPS no problem, as it should. However, the GPU soon overheats (around 80 degrees celcius) and audio going through the graphics card becomes incredibly distorted, while the framerate takes a huge hit. I have observed it many times and it is a clear pattern: The card gets really hot and the framerate drops are accompanied by distorted audio.

Audio sounds fine when going through the sound card instead of the graphics card. The framerate will still drop but the audio will not become distorted unless it is going through the graphics card.

One thing I noticed was that, using the original nVidia drivers, the card performed worse overall but did not overheat. It seems to me that the newer drivers automatically overclock the GPU and then, when it gets too hot, they tone it down so it will cool down. I would rather get a consistent framerate than have my card run really fast for a minute, get super hot, then run really slow, back and forth. My X51 shouldn't be performing worse than my M14X (an Alienware laptop) in Saints Row 3 with the exact same graphics settings.

There is plenty of air around the X51 and the room is quite cool. I could even blow a dust-filtering fan directly on the X51 but it isn't enough to keep the GPU cool. What am I supposed to do? How can I stop the GTX 670 from overclocking if that is what is happening?