There is not enough information in your posting to offer any suggestions.

Changing from modules to classes, if done properly, should not change the 
speed of your application.  Have you also changed the way you query the 
database?  Are your connections going away where in the old design they 
were staying in scope (and active)?

I suggest:
  *  refactor one piece at a time and do a timing of just that piece to 
see if things have slowed down.  Break you rproblem into smaller bits.
  *  Make sure you do not have too much expense in getting an object 
created.  Keep your Class_Initialize code to a minimum.
  *  Try to compare timings of smaller granules.  Since the code in the 
class will look very similar to what it did in the module, time 
individual routines and try and find the problem.

R

> I've been converting an Application to use Classes as much as possible,
> to remove the SQL code from the Application and make sure it's 
consistant
> across the whole App.
> 
> However, I'm finding that the App has slowed down considerably :(
> 
> So, the question is, what can I do to get the App back to speed again?
> If I have to I guess I can reinsert the SQL code directly, but I'd 
prefer
> not to...
> 
> R.