What about bloat? You might be suffering from rapid expansion of the file sizes so check that for growth. Are you storing documents/images in tables? Are we talking regular use here or frequent design changes? Did you try compact/repair instead of relinking to see if that solved your speed issue (until next time)? If you've never used the feature, I would make a backup copy of the db before doing so for the first time.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.