Stuttering video

I have a new Raspberry Pi 2 that I hoped would fix my stuttering video issues but it has not. When streaming from a samba share on my Win 7 (32-bit) Athlon II X2 240 I get constant stuttering. Sometimes it says buffering, mostly just freezes and eventually starts and pauses throughout the video. When I stream the same file from my Win 7 (64-bit) Phenom II X6 1090T I have no issues what so ever. I know the Phenom is a much better CPU but it used to work fine back when I had raspbmc and it was the earlier releases. Since Kodi/Helix/OSMC I just get these stuttering problems. Any ideas would be great as the Athlon is on 24/7 but the Phenom is not always available as a file server.

As providing a Stream is not that much work for the CPU, i would suspect the network connection. Are both servers connected via Ethernet or is wifi in the game? Have you tried setting up a ftp-server on the win7 machine to bypass possible smb configuration problems?

Both PC’s and the Raspberry Pi are connected to the same gigabit hub. I did some more messing around and came up with this test:
The Athlon PC (server) is running Kodi 14.1 with a MySQL database shared to my raspberry pi’s and my Phenom PC. I used OSMC to connect to the uPnP server on my Phenom running Kodi 14.1 which then played the video from my Athlon’s hard drive to the Raspberry Pi and it worked perfectly.
For some reason the Athlon to Phenom works but to the Raspberry Pi (i’ve tried 2 B’s and a new Raspberry Pi 2) it stutters and buffers. I’ve even swapped ports on the hub with no luck.