As far back as I remember (I think I’ve been playing with this software, on and off, since 2005) I’ve noticed that the longer I work on a scene, the slower the response becomes. Eventually I need to save everything and restart.
I seem to remember way back that there were memory problems where used memory space would not be released and paging in and out became an issue which slowed down the response times. I’m no software expert so I can’t really comment, but it seems to me that whatever the problem, it has not been solved. I can say that the longer I work, the more I notice the disk activity. This might be explained by paging in and out, I don’t know for sure, but I note that the disk is constantly beavering away in the background. I thought it might be Windows doing a scan or doing some indexing but I checked and made sure the indexing service was turned off and that there was so scan scheduled. Besides. the disk activity stops when D|S is closed.
My system is Windows 7 Pro 64bit, i7 8 core and 8Gb memory so it should be up to the task. The symptoms, by the time I decide to restart, are: camera rotation slow and jerky, joint movement (bend and arm, turn the head, etc.) so unresponsive that I think I have not actually made a change - then it will suddenly jerk to some extreme position.