Historically I've found it pretty good - but I think I am lucky in that I play hours when there are not many false reporters and/or early enders around...
I find it easy to use the notifications as well...my setup is..
TT in window mode; internet browser open as well - either on TTC or other pages; or sometimes my Google Email account (the tab at the bottom shows the number of unread emails - and I can watch for the number increasing - which might be an invasion notification).
And/or I'll have the google desktop/side bar (see right hand side) - so I can read the title of new emails .. and keep an eye on how my PC is holding up via the System Monitor...
the concept of TIPS is struggling with the new invasions though - there are so many of them; not sure it has the up to date districts
re: the freezing - are you running in window mode or full screen??