Buffering while playing 4k mkv and iso files

I have connected my apple tv 4k over a gigabit ethernet to my nas and i have set my smb setting to legacy but still it stutters while playing full 4k bluray iso and remux mkv for every 2 mins approx.Any solution to this.I bought my apple tv 4k mainly for this purpose.Now i feel i should have bought the nvidia shield tv instead. Kindly help

What type of NAS are you streaming from? Do you know what versions of SMB are supported/enabled on that device? Have you tried changing Infuse to SMB2 to see if that helps?

You can also try connecting via NFS, as that may perform a bit better with certain devices.

I use synology DS218j.It even lags when i use the files from my pc.Suggest the best hardware for bufferless expierence.I dont mind in changing to that.I just want the best playback on 4k iso files.