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 have some annoying disadvantages even today; eg they serve too few users at a time too slowly in 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 try to investigate the role of three-level data modelling in an indirect way. I, with a colleague of 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 poorer environment.