Warning-dropping frames and video stutter.

Hi folks, Video footage i'm editing in FCPX is skipping and stuttering on me and I'm getting the warning that frames are being dropped, will startting again and creating proxy media help me improve performance, I'm working off an external drive but it's only a usb key, is this effecting performance also? Should I work off my internal hard drive? It's quite full itself.
S

You'll never get smooth performance via USB, unless it is a real USB 3.0 hard drive, and your Mac is new enough to support USB 3.0.

In Preferences > Playback, set to Better Performance.
Turn off the dropped frame warning, we know its dropping frames.

Thanks it's already set to better performance, i've chenged preferences to proxy media on import should I change it to proxy media in playback also i presume?
Should I copy files to final cut events folder then if the usb key is not smooth?

Create Proxy upon import, set Playback to Proxy to help during editing.
But when you export, you want to change Playback to Original/Optimized.
If you import the original into the Event folder, or simply Optimize it, is personal choice, but you'll need to do one or the other, along with creating Proxy media.