In Hungary there exist two big and well-known scholar information systems (SIS).Both of them have become part of everyday life in the administration of higher education.These SISes have made quite a long journey during their evolution. Even so, they havesome annoying disadvantages even today; e.g. they serve too few users at a time too slowlyin the case of critical activities, such as during registration for courses or for examinations.There are many circumstances which can result in such poor efficiency. In this paper I tryto investigate the role of three-level data modelling in an indirect way. I, with a colleagueof mine at Budapest Tech, planned and executed a measurement which shows that (much)better performance can be reached based on a 'good' data model, even in a poorerenvironment.