My Macbook has been running fine since I installed Snow Leopard. I leave it on, usually in suspend mode often. This morning, I went into my office and I heard the fan blowing. I pressed a key and there was nothing running. It was at the desktop, as I left it. I checked iStat pro and the fan was running over 6000rpm, normall it's 1786rpm or something like that. I rebooted it and it was fine, but that has never happened before. I also noticed that after I installed Snow Leopard, it was fast to boot up and shut down. Now it takes longer again, similar to what it was using Leopard, maybe slower. Performance once I am loaded up is fine though.