Initially, I found that Carrara 1 and 1.1 had difficulties, though the Eovia 1.1 patch did solve some issues. Now at version 2, however, I find Carrara to be a solid performer on my system. I am running Win2000 SP3 on a dual P3 processor board, with 512 of RAM. I would say that in my case, the upgrade was worth the money I spent.