Windows 7: GTX 550 Ti Overheating Symptoms at 50°

Hello. I'm having an issue with my Zotac AMP! GeForce GTX 550 Ti where it seems to be overheating at a low temperature. While playing Skyrim (low or high settings), at some point my sound will become very tinny and the game will drop to under 2 FPS about every 30 seconds. Most recently, Windows Aero disabled itself without an error message of any kind. After much frustration, I discovered that this only occurred when my GPU reached 50° and above.

To me, this seems odd because I thought cards could perform at temperatures well over 70°. I'm also confused as to why this would even be affecting my sound at all. I've disabled all HD audio devices with NVIDIA drivers to use my Sound Blaster X-Fi Xtreme with drivers from Creative. I should mention that in order to get my GPU fan running at an appropriate speed, I have to manually set it to 100% with Zotac's OC utility FireStorm. I recently added three 120mm fans to my case. Does anyone know what could be wrong here?

Maximum GPU Temperature is 100C
Is the GPU OC'd?

Here is a relevant article for you:

Nvidia GTX 550 Ti Temperature Problems and Solutions

No, it's not overclocked at all.

Who's to say its a GPU issue? dropping for frame rates could be ram and processor related as well, both could also cause sound issues.

Oddly you don't have a sound card? That could be defective causing all the symptoms.

Try: DPC Latency Checker

DPC Latency problems can cause drops in audio/video.

Well, in an attempt to diagnose the problem, I ran Skyrim with absolutely minimal applications and services running on my OS. I should probably take the time to give you my specs:

OS: Windows 7 Ultimate x64
CPU: AMD Athlon X2 6400+ (3.21 GHz)
RAM: 4 GB (DDR2 800 MHz)
GPU: Zotac AMP! NVIDIA GeForce GTX 560 Ti (1 GB)
Sound Card: Sound Blaster X-Fi Xtreme

As you can see, I do have a sound card. Sorry if I wasn't clear about that. Given that I have a sound card with its own drivers and that I've disabled all devices with NVIDIA sound drivers, that is why I was confused about the audio problem. Because my RAM doesn't typically raise above 50% during gameplay, I wasn't considering it a potential cause of the problem.

The CPU usage, however, reaches 100% during every freeze I have in-game. Keep in mind that this occurs with networking, antivirus, themes, audio, and most other non-essential programs running in the background. I'm going to try DPC Latency Checker and get back to you guys with the results.

Update:
I ran DPC Latency Checker while playing the game, and it stayed in the green the whole time. The good news is my game isn't freezing anymore when I set the GPU fan to 100%. I get slight FPS loss, but that's probably due to the hi-res textures I've installed and the fact that the settings for Skyrim are on Ultra. I am still having issues with the sound after about 5 minutes of playing, though. The sound suddenly becomes very tinny, and it seems to deteriorate over time. I noticed that CPU spikes to 100% very frequently.