Trouble with BDP-S570

I was successfully using Serviio 1.2.1 to serve to my BDP-S570 with transcoding off. I upgraded to 1.3. Anything served to this player now stutters horribly. In the past, I have had this issue and fixed it by uninstall/reinstall of Serviio, or a previous version. This time, that does not work. I went all the way back to V1.0.1 with no success. My Samsung player works fine, it's just the Sony.
I am running Windows 8 on Core I7. My players are connected via Ethernet; no wifi. There is a Linksys network switch between my computer and the player, but it's always been there.
I removed Serviio and turned on Windows streaming. This works with both the Sony and the Samsung. However, I much prefer Serviio for a variety of reasons. If it turn transcoding on, Serviio DOES work with the Sony, but my computer gets pretty busy, in particular hard drive accesses. I would prefer to not transcode. All of my video files are H.264 MP4 containers. I have successfully played the MP4 files via USB on the Sony player.
I have searched the forum, but I did not find much on this situation.
I'm wondering if there is something that is NOT included with Serviio (i.e. a dll or something) that is causing this, but I have no idea where to look.
Any ideas would be appreciated.
I am running Windows 8 on Core I7. My players are connected via Ethernet; no wifi. There is a Linksys network switch between my computer and the player, but it's always been there.
I removed Serviio and turned on Windows streaming. This works with both the Sony and the Samsung. However, I much prefer Serviio for a variety of reasons. If it turn transcoding on, Serviio DOES work with the Sony, but my computer gets pretty busy, in particular hard drive accesses. I would prefer to not transcode. All of my video files are H.264 MP4 containers. I have successfully played the MP4 files via USB on the Sony player.
I have searched the forum, but I did not find much on this situation.
I'm wondering if there is something that is NOT included with Serviio (i.e. a dll or something) that is causing this, but I have no idea where to look.
Any ideas would be appreciated.