Problem Using FindNearest with Interbase

I am writing a Database application using Delphi 3.02.  I started using
Access95  as my Database. What a dog! It took forever to Open a Database
with 6 tables ranging from 2 to 8000 records. I then decided to switch to
Interbase which was much faster. The problem I am having now is the
following:

One of the tables contains about 8000 records with the following columns:
City_ID, City_Name, Province, ZIP, Country, Code, Attribute1, Attribute2 ...
Attribute5. I am using an index on City_Name.  I then created a simple test
which uses a DBGrid, and a TEdit with the following code on change :

procedure TForm1.Edit1Change(Sender: TObject);
begin
   Table1.FindNearest[(Edit1.Text]);
end;
where table1 is the table in question.

When I connect to the Interbase Database, it takes well over 3 seconds for
the DBGrid to be updated as I type a new character. I then tried using the
same table stored in the Access Database. The retrieval time was almost
immediate.

I am using a P5 200MMX with 48M of RAM.  Is this problem unique to
Interbase?

I would greatly appreciate a reply.

Regards
Renato