Defragging 3 times a day would seem to be over the top. For most users weekly would be perfectly adequate but I guess it really depends just what you do.
Historically Pioneer burners seem to prefer to be the master device or so the general opinion on this forum suggests. Don't know how true that really is.
I see you've got the Intel Application Accelerator driver installed. I seem to recall some issues with this but I can't remember the details.
With an 8 minute burn at 8x I can't think there can be too much wrong.
I don't think I have much more to offer.