I have some apps which create temp tables and fill it will transaction data
as needed. These apps
run flawlessly, except for some transactions the apps will delay for several
seconds after writing
the temp tables. On some slower machines of our users, it seems that the
system is hang. Any idea?

Many thanks

You're not giving us much information on the working environment.
Some delay may be the physical writing of data to the hard drive.
If you have a virus checker that is checking for every file opened,
that's probably what's slowing things down.