According to Digidesign, these problems can stem from issues with Applications that bypass the Windows API for timing by directly using the RDTSC (Read Time Stamp Counter) instruction. This can be remedied by installing the AMD Dual Core Optimizer and the Windows Dual Core Hotfix.
You can find a link to the fixes below at Digidesigns site.
– Download and install the AMD Dual Core Optimizer from the AMD website.
– Install the Windows Dual Core Hotfix from Microsoft’s site (failure to complete all instructions will make this fix ineffective).
This applies to ALL Dual Core AMD Processors.