Just been searching for issues like this. I'm trying to clean up a mocap clip with the curve editor and it's desperately slow. It's taken over two minutes to delete three keyframes. I'm now waiting a few minutes to select several joints to optimise them and reduce the hundreds of thousands of data points.
I can't make a film if it takes an hour of waiting around to clean up a single mocap file
One of the issues looks like the curve editor is single threaded - only one of eight cores is doing anything. The rest of the iClone suite appears to use all cores (Character creator 3 for example). I am using the trial at the moment but surely performance isn't crippled in the trial, or if it is, it puts the product in a very bad light.