Disable them in the device manager?
You have to know this first... I have the same problem with the same speakers
using the onboard audio.
Using a cheap set of speakers like the T20 of Creative are causing no problems.
Those studio monitors from Quad (high quality) are more sensitive.
I think that removing de sound card out of the case could help he.
Replace the sound with an external music module and connect with USB.
But I understand, it' s not a solution to the inside problem
I just learned that to disable the Speedstep is not an option here...
Not good for the CPU > gets to hot etc.