Kodi is a great media center period. Just alone without 3rd party add ons its a very powerful piece of software. But having large HD files streaming from sources or in your local network can sometimes buffer. There are some options people use such as preconfigured advance settings. Everyone in the community has some work around etc. For my self and others we’ve had major success with these settings. Check out the video below from a YouTube user. We have tested this on the Amazon Fire TV, Amazon Fire TV Stick, Minix Z64, Raspberry Pi, and other Android set top boxes. It is pretty much trial and error. Keep in mind buffering occurs from either a bad link, slow internet speeds, bandwidth load on the links provider, etc. Try it out and see what works for your device and adjust accordingly. Keep in mind on how much RAM your device has and adjust from there.
Start with these settings and if it works then thats great. The example below goes as is.
1Gb of ram Amazon Fire TV Stick/Ouya, and any other Android box that has 1gb of RAM
For every 1gb of RAM you multiply by 209715200
cache-209715200 read-4.0 buffer-1
209715200=20mb so that gets multiplied by three.
So 2gb of RAM on a device such as Amazon Fire TV would be cache-419430400 read-4.0 buffer-1 that means 419430400 =40mb *3=120mb adjust accordingly to your connection. These have worked well for me. I live in CA, USA and have a 50mb down internet connection. So this is just a formula to work off of.