I am using V3.3, and I still experience the similar performance problem with large models. Even for small models, if I leave the modeler to run for a long time, it becomes slower and slower over time. Last night, left the it to run a synch with the dictionary, and this morning, the program pretty much stopped responding and running ( indicated by 0% CPU). I am not sure if the synch was done. After I tried a few times of resizing and waited for long time, it displayed the menu. So I clicked on Save, then again it hung and never complete the save. Took forever to complete the repaint of screen. Seems have some memory leaking problem. Is Oracle aware this kind of issue? What is the largest model that Oracle tested on the release of SQL Data Modeler?