You do realise that both DBMS have a job to do. They both need to
store and retrieve data, serve user requests, and do enough
housekeeping to efficiently do it.

Database engines are generally resource hungry. They will demand I/O,
CPU, and RAM (although I suspect that MSSQL will want more of that
than FB). You haven't made clear what you meant by "just installed".
If you mean that you have installed the service, have not installed
any databases etc, then I would be looking elsewhere for your problem.
If you are running queries against Firebird, then it doesn't take a
rocket scientist to work out that I/O, CPU and RAM that could have
been entirely dedicated to MSSQL now has to be shared with FB.

As far as your second concern goes, it is not difficult to back up the
aliases.conf. As far as the Firebird.conf goes, there are some things
you want to set to optimise for Classic (like switching off guardian etc).

Adam

> Additional note :
> Long report for MSSQL is completed after 35 minutes when Firebird
> service is disable and after more then 60 minutes when Firebird is
> running (as IT staff said).
>
> How can I change instalation of SuperServer into ClassicServer without
> uninstalling it (I have changed aliases.conf and firebird.conf and would
> like to preserve them) ? Could it be solution for my problem ?
> I appreciate any help.This is very annoying that I must prove Firebird
> comapatibility with other programs :-(
>
>
> Regards
> Boguslaw Brandys