geoyul93 :
i have GPU asus gtx 1050 ti strix oc 4gb but when i open mv in 4k resolution it so lag, it's that mean GTX 1050 ti not support 4k video ?
It supports 4k video playback just fine.
You have to use appropriate video player for that (one that can use dxva) or else all video processing is done by cpu.
Try Media Player Classic Home Cinema.
https://mpc-hc.org/