I just recently acquired a Compaq Presario 2200 desktop from 1997. It has a Cyrix MediaGX processor, so the CPU, GPU and portions of the audio chipsets are all integrated. I have noticed that the audio on the 2200 has SEVERE RF interference problems, particularly when moving the mouse and accessing the hard drive. Here's a recording I did showing how bad it is. I got this by running a cable from the line out port on the Presario to the line in port on my netbook.

https://dl.dropboxusercontent.com/u/68314417/ … Audio%20RFI.wav

First, the hard drive spins up from sleep mode and reinitializes itself. Then I move the mouse around a bit, and load up a couple programs to put the hard drive under load. Lastly, I move the mouse around a little bit more.

You can hear just how bad the interference is. This is from the line out/speaker port on the back of the system, so it's the entire audio controller that is picking up this interference and not just the internal speakers (which I did notice use unshielded cables).

Considering how old and heavily integrated this system is, I'm doubtful there's much if anything that can be done. But, is there anything anyone could recommend to at least reduce the interference? If it helps, here's a couple pictures of the motherboard.

UPDATE: From what I can determine, this computer actually has two onboard sound chipsets, the integrated MediaGX XpressAudio and a separate SB16 clone (Presumably that Analog Devices chip on the motherboard). If the MediaGX sound driver is not installed, then Windows will default to a SB16/AWE32 PnP driver with a totally different FM synth and overall "sound style" to it, for lack of a better description. However, even when using the SB16 audio, the RF interference remains, so it's not a driver problem.