Thanks for the reply! I selected all of my thumbnails and generated 1x1 previews for them all. That seems to have helped noticeably. I'm going to add double the memory in my computer to a total of 8GB this weekend.I'll update this thread once I see how LR performs with 8GB of memory.
I don't understand why LR continues to allocate memory to the point that LR no longer performs.There are a lot of programs out there that manage their own memory instead of relying entirely upon Windows memory management.