Well, my drives are not external hard drives. My server has an Acrea ARC-1882-ix-16 with SAS 6Gb/s drives. RAID 6 Array.
I tested several different methods including OS changes etc. Windows 2012 Server and Windows 7. I have also tested with internal SSD drives as well.
My HTPC is full ATX, but I built it to run quiet. Although, I didn't like the video quality from Ivy Bridge, so I switched to Nvidia 760 GTX.
My network is a Cisco Smart Switch (Small Business model), but it is mainly for my home automation setup.
My receiver is Denon AVR-53008, which has a Silicon Optix Realta HQV video processor chip to upconvert DVD to 1080p.
I tested all known posts on this problem, but I was about to give up. Then I set up JRemote and it works fine now. Bluray is a separate issue, but it is nice to have JRemote control all your media without switching libraries.