Zimm, do you have RivaTuner installed on your computer? It's an extremely useful program, and really a must have (I use it), that allows you to monitor the temperature of your video card and possibly other stuff.
Once you have the program set up, it will automatically change fan speeds based on temperature, or you can do it manually.
I don't have that, but the XFX Radeon HD 4870 X2 I use has a built-in software control panel that does all of that and lets you manually control the overclocking and fan speeds while monitoring temp, memory use, etc, or you let the system monitor those. I also think my CPU has a similar control panel but I'm not messing with upping the voltage on the i-7 CPU - at least not yet.
