Unsound 5102

Hope it's OK to start a new thread about this. I believe I have now started to nail the problem, but not the answer.

Aspire 5102 now running Vista. I have several audio problems, and would be very grateful if anyone could check to see if their machine does the same. I can show the problems on most audio, but it is very obvious if I play my test wave file consisting of 1.4kHz stereo tone at -6dB for a duration of 100 seconds. The Vista installation is just the basic Vista plus the Realtek and 8.31 video drivers. I've removed all the Acer e-programs, which seemed to cause separate audio glitches.

1. With the internal Realtek soundcard, if the volume is up too high, all sorts of problems occur depending on what program is playing the audio. The problems include gaps in the audio playback, problems with the video display not following the sound, and with more complex programs (eg Adobe Audition 1.5) the program and rest of the desktop becomes completely unresponsive until the audio stops.
Running Ubuntu Linux from a Live CD shows a similar effect. Reducing the audio level to pretty quiet in either OS removes the problem completely.

Installing an Edirol usb soundcard and making it the default sound device cures the problem now that I've discarded the Acer software.

The problem doesn't appear to be heat related, and I can't see any dust near the fan.

2. I can't get the 8.352 ATI video driver from the Acer ftp site to install.

For problem 1, it seems to me that the audio amp, when it is presented with a constant signal and thus draws more current, may be starving some digital parts of the motherboard of power. What I need to establish is whether this is correct and, if so, whether it's a design fault or whether I have a faulty machine.

If anyone can help by trying this on their machine I'd be really grateful. If producing a test audio signal is difficult I can probably email it or perhaps find somewhere to post it.