My Droid (MotoDroid 1) starts to get really slow when the free memory falls below about 18%. I'm finding that if I let the Droid do its thing, the free memory routinely falls below 15%, and the phone is so unresponsive that it's frustrating to use. I also see other symptoms that appear memory-related, like screen artifacts (or screens just not being drawn properly), hiccups in video playback or game motion, etc. I installed a memory manager app/task killer (Memory Booster Lite), and when I kill the active tasks my free memory boosts to about 30% and the phone works great. The problem is that almost all of the tasks that are running are programs I'm not using, and in many cases haven't used in days or weeks. When I kill them, things are great, but I can then watch as the Droid loads different items into memory. Again, it's loading programs I haven't used recently. So why is my Droid stupid enough to keep loading programs that slow it down, and how do I stop it from doing it more?