Thanks for letting me know MarshalJean.
I haven't experienced that type of problem where the units and sounds lag or freeze, but if I had to guess I'd say it is the marching music. Those files are quite large. What armies were you using at the time? Can you try renaming (so they don't activate) the marching music files within the countries modded sound folder?
If it turns out they are the problem, I can try trimming the tracks and/or resampling to reduce the file size.
