Thanks for this diagnosis, et voila (and stief for posting the screenshot). We'll take a closer look into downloads. Unfortunately, it seems like 80/90MB footprint when running as an ultrapeer is going to stay for a bit... I believe the problem ultimately stems from QRP tables taking up too much memory. There doesn't seem to be any efficient sparse bitset representations for java, and making one is a very difficult (and time-consuming) task. Even sparse matrixes seem too heavyweight.