NOTE: The procedure described here might be completely unnecessary - see this later journal entry.
My main desktop machine (gold) is a dual-boot Windows 2000/Debian GNU/Linux environment. As a sound card, it has a Hoontech (now ST Audio?) DSP-24 Media 7.1. Some time ago I'd noticed that intensive CPU or I/O activity would cause Internet radio to sloooooow right down, with an equivalent drop in quality. I tried messing with buffering, different client programs (RealPlayer, winamp), but nothing helped.
I suspect the sound problems stemmed from around the same time I put a new network card in gold, but it's hard to remember...
Forced finally to read the soundcard manual, it suggested that shared IRQ's could be one cause of performance problems. It also stated that ACPI under Windows 2000 could cause stability and performance problems. The recommended solution was to install Windows 2000 with a non-ACPI option. Too late for me; it was definitely ACPI under Computer in the Device Manager tree.
On checking the IRQ assignments at boot time, I noted that the sound card and ACPI shared IRQ 9. Perhaps this was the cause of the problem?
My first solution was to remove the old D-Link network adapter, to see if this would shift the IRQ assignments around. It did, and now the sound card and ACPI were on different interrupts. However, it made no improvement to the sound.
I bit the bullet; turned off PNP in the BIOS, then installed the Standard PC driver in place of the ACPI driver. This latter step can be achieved by right-clicking on the existing ACPI Computer entry, selecting the driver tab and re-installing the driver. Request Windows to produce a list of suitable devices, then select Standard PC rather than ACPI PC.
With some trepidation, I rebooted. As predicted by the soundcard manual, Windows 2000 needed to re-install all the drivers. This was mostly OK, but selecting driver locations without a mouse is an exercise in frustration.
Finally, I had the PC back in a working state. And, hurrah, the sound now played perfectly, irrespective of the CPU load. My only problem now is that the machine will not power off automatically on shutdown with ACPI disabled. Somehow, I have to enable APM, but there's nothing available in the Control Panel, Power Options. Some more research is required.
A little later, after a small amount of research, I turned up this article from Microsoft. It explains what to do to enable APM, which involves ensuring that the ACPI driver (under non-Plug and Play Drivers when you "Show hidden devices" via the View menu in the Device Manager window) is disabled on its property page. Once this is done, you can reboot and install the "NT APM/Legacy Support" driver, and finally power-off on shutdown is back.
