Screen problems ?

Hi, I have just upgraded an application from Aix 2.2, Informix 4gl v1 running on an IBM RT. The system is now running on a Pentium 150 server with 48megs of RAM, running SCO Openserver 5 and Informix 4GL latest release, with the latest release of the Standard Engine. Anyhow, the problem is this - the users are complaining that their application screens are now "jerky". For instance, when displaying an informix form to the terminal, the form with build to 75% of the screen. There will then be a short pause and then the rest of the form will be displayed followed by their query data. The terminal emualtion is perfect using TERMCAP (informix). I am not so sure that this is a problem, rather it is just the way the screens build. Anyone got any ideas. i.e. is this just the way things are or should I be tweaking something to make screen building and scrolling more flowing ? Any comments gratefully accepted. Cheers, Sean.