[PK21]

Android is currently only able to output at 60hz so any 24p content will always undergo 2:3 pulldown. That said, the stuttering effect caused by 2:3 pulldown is usually quite subtle, some people never even notice it, while others may be more sensitive.
So the crucial question is, what is the native refresh rate of your screen (TV)? If it is 60hz then all 24p content should stutter the same regardless of what device you use to play them (they will all eventually have to be 2:3 pulldown, either by the device or by the TV itself), and if you perceive more stuttering on the Fire TV than on your HTPC, then something is wrong with your Fire TV. If however your TV is 120hz or 240hz, and you configured your HTPC to push native 24p to the TV (you would be a moron not to , then it's much more likely you've gotten used to stutter-free play back on your HTPC, and are just experiencing the normal 2:3 pulldown induced stuttering on the Fire TV.

I have the same problem with a Gotham build and it happens consistently. Here is what I know:

1) For me, it only seems to happen with AVIs and is just noticeable when panning
2) 720p MKVs and ISO files play fine with no stuttering at all.
3) This problem does not occur with Frodo or Openelec on my PC.
4) This also does not happen with my WD Live player.

Again, for me, it only happens when playing AVIs.

Hmm, does sound like a software problem then. Have you tried repackaging the problematic AVIs into MKVs (with mkvmerge or similar tool) and see if it still plays the same? It's much more likely the type of video stream is causing the problem rather than the container format.

I believe you're probably right about repackaging. Problem is, I have so many AVIs and didnt have this issue with other players. I'm afraid I might have to bite the bullet one day and repackage them all. Sure would be nice though if I could get them to play smoothly without repackaging.