I have a complicated issue here. I recently hooked up a 22" screen to my iMac to use as a second monitor. Everything has been running great and I love the extra screen space. But I noticed that when I have any window open on the main iMac screen, the CPU usage on finder would just jump up to 50-100%. But when I close that window or use expose to go to the desktop, the CPU usage would go all the way back down. I remember seeing someone on MacRumors who was having the same problem but he didn't have his problem resolved. So I'm wondering if there's any way to fix this issue or if it's a hardware problem?
BTW, it's any application with a window open, not just finder, I'm currently using firefox on the smaller screen because of the CPU issue.