I was having major problems with playing back videos in MPlayer, with jerky, unresponsive video playback. I could get better performance out of VideoLAN, at the expense of dropper frames. That and VideoLAN tends to start playing your media, and the video stream won't show up for the first 10 seconds. Vert y annoying. I tried closing ALL other apps. Even the Finder, and performance was still bad. But then I remembered something I saw in the Activity Monitor when I had to go and kill a process manually a short time ago. Taking the initiative, I went and fixed the problem. 30 seconds later, my system was back to normal, and videos were playing fine. What did I do to fix it? I closed every single Dashboard widget. Yep, those Widgets use up waaaaaaay too many resources. Let me give you an example. Ok, I'm gonna open up Activity Monitor. Now, I currently have NO widgets on my dashboard. I'll go add two World Clocks, one Weather and one Stock Viewer. Now, lets go check the Activity Monitor. World Clock DashboardClient is now using up 10.16MB of real memory, and 119.43MB of virtual memory! Weather DashboardClient is using up 11.59MB of real memory, and 120.11MB of virtual memory. Now, this is with just FOUR DAMN WIDGETS. Imagine what would happen if you had many, many more open. I would think that a few of us do... So, in conclusion, if you want to help speed up your system, cut down on your Widgets. Or do what I do. Don't use the Dashboard at all.