plugged the speakers into her? *giggle* sorry..
hehe, I like the approach
cisco 3550 at home
have you modded it as well to be little less noisier?
What is occasionally? every 20 minutes or 5 minutes?
Always same place in the movie?
Well just a thought from my side, Are you doing anything else at the same time that needs processing at the core?
Since I am not a daily linux user I can't recommend a program/app to run but how about monitoring cpu and memory for a longer period and then review when this happens if it has to do with cpu/mem
Have you checked the network traffic with for example wireshark for dropped packages, package delay or similar?
Set it up so you do port mirroring on the interface towards the core and then review it later. Even better do a merge cap of two files like interface to the core and the interface to the media directors.
I also don't think increasing the package size will help. Off course, the bigger the better(in some cases)
You are using Raid5 for the media data?
From performance perspective I belieive Raid 0 or 1 would be better. Can this maybe be the cause?