When you capture video clips, Final Cut Pro may interrupt the capture process to tell you that it's dropping frames while capturing, which means that the hard disk is not recording all the frames of video that are flowing from your camera in real time. Captured clips that are missing some frames play with slight stutters or pops, so Final Cut Pro thankfully warns you that this is happening ahead of time. If you're dropping frames during capture, consider these culprits:

• The hard drive isn't fast enough. Lots of factors determine how fast a hard drive can write data, but a major one is its rotational speed — that is, how fast the drive's physical magnetic disk spins. Older 4200-rpm drives can drop frames, but drives with 5400- or 7200-rpm ratings should be fine.
• The hard drive is fragmented. Fragmentation happens over time when a lot of files are written to and deleted from a disk; when you're saving a large video file, segments of the file may be written in different places on the disk. Therefore, the disk's heads must move back and forth across the disk, which slows performance — your drive can't record the frames fast enough. You can defragment your disk by using a utility such as Norton Utilities.
• The hard drive is too full. If a drive has only about 10 percent free space, it can lose enough speed to start dropping frames. The solution: Delete unnecessary files or buy a larger hard drive.