Number of transactions in database



I am using Darhon Finance 1.3.1 for quite some time now.
It is a very easy to use application and finally I can
use it on Linux, N900 and recently on Windows 7.

I do not know how many transactions there are already in the database
(is there a way to get information about this in Darhon Finance 1.3.1 ?),
but the thing is getting a bit slow now on N900.
I have to add, that I transfer the database to Linux and back to N900 quite
Is there some way to make it faster?
What is the maximum number of transactions?

Best regards