For slow devices (e.g. BD-D5300) I recommend to decrease the buffer sizes.
Go to Preferences -> Player and set them to:
Initial Buffer: 1MB
Pending Buffer: 1MB
Total Buffer: 1MB
For normal devices (e.g. D6500) I recommend to set the buffer to.
Go to Preferences -> Player and set them to:
Initial Buffer: 5MB
Pending Buffer: 10MB or 15MB
Total Buffer: 15MB or 20MB
For high bitrate movies (17mbps+) I recommend to increase the buffer sizes. But this doesn't work on all devices. Some just can't play high bitrate movies (e.g. BD-D5300)
Go to Preferences -> Player and set them to:
Initial Buffer: 25MB
Pending Buffer: 50MB
Total Buffer: 75MB