I'm running it from a HDD. Other games are working fine (zeldaSS...). But on the last story, I have a "slow motion" feeling + frequent slowdowns on town. As it's really noticeable and sometime almost unplayable, I think I have a problem you don't have.
Where do I have to look? Can it be related to something outdated on my wii?
Sadly the framerate wasn't fully optimized for the Wii.
Even using the original disc will give you those issues.