Debug compile (dumb question)

[neFAST]

Hi everyone, I recently formatted my hard-drive and resinstalled:
a fresh MM3.0
a fresh MM3.1 (latest build)

With MM3.0, I takes ~3sec to display the panes with my ~30k library
WIth MM3.1, this time reach 20sec.

It there something wrong with my library? Or is it a consquence of the debug compile of MM3.1?

Thanks a lot for your help!