Buffering Issues on FreeNAS/Plex

I built a FreeNAS server and it has been running great. I can transfer anything to and from the NAS at 110Mbps which is the maximum for a gigabit network.

Specs
Dual Processor - Intel Xeon® CPU E5-2609 v2 @ 2.5GHz
128GB ECC RAM
Dual gigabit NICs
(6) 4TB Drives
FreeNAS: 11.1_U4

I installed the Plex Media Server plugin which runs in a FreeNAS jail.

When I stream a movie from this server I randomly get buffering issues. Watching a 2hr movie it will pause and buffer 4-5 times. Most of my movies are HD 1080p (MP4 x264) but some of them are SD 480p and even those buffer. Usually we’re just streaming one movie at a time.

I even setup three computers and streamed three different movies all at one time and they work just fine. Then all of sudden I get buffering across all devices.

I’m not sure this is a transcoding issue. I should have enough horsepower. I have noticed when opening a browser sometimes I get a message that the plex server is not available. Then it pops up and everything is fine.

I’ve at my whits end trying to get this working. Any help would be greatly appreciated.

Thanks
Brandon