Processor affinity

I have an Intel Core Duo processor in my laptop, giving me multi-processor capability. For some reason, DOpus always starts with processor affinity set for just CPU 0. Is this done on purpose? If not, how do I change it so DOpus will use both processors by default?

That isn't normal and I don't think Opus would ever do it to itself.

Perhaps a shell extension or video codec is setting the processor affinity? Is it like that if Opus has just been restarted? Is Explorer.exe the same?

Presumably you're not running any 3rd party "CPU balancing" tools or similar.