TLDR: I get buffering when I do not use a VPN, when I am on VPN, no buffering.
I am a neophyte when it comes to IPTV stuff, last year I did SetTV for NBA playoffs, then did nothing till about a few days ago and tried Vaders.
My ISP is Comcast Business, at the time it was the cheapest option for internet with out TV.
Anyway, this is just me experimenting with this over the last few days and I only get buffering when I do not use a VPN. It may just be random bad luck.
My guess is Comcast puting limits on my bandwidth when it sees me doing things it thinks might be shady
NVIDIA Shield, Vaders, VPN Unlimited, Comcast Business.
And all may be dumb luck.
we all know this subreddit can be full of people selling stuff and basically being full of shit, but look over my history of posting, I am selling nothing, and freely admit I may be 100% wrong in my assessment.
Peace, have a good one.
If it's not buffering with VPN, then stick with it. It sounds like you are being throttled by the ISP.