UI Sluggish

I have the latest firmware. I’ve noticed over the past couple of weeks that the UI has become very sluggish, especially when moving and deleting files. It can take several minutes to complete the process (including the update of the library). The good news is it doesn’t seem to affect playback at all. I’m wondering if perhaps it is firmware related and others have noticed this? I have about 250 MB unused on the internal hard drive. Is there a point where the hard drive is too full and performance suffers?

Sometimes my Hub gets sluggish and I have to reboot the machine.