MPV works fine but SMPlayer don´t

Hi, I tried to install MPV with SMPlayer interface in Manjaro Linux with vapoursynth support.
It works fine with SVP if I open the video through the SVP open file menu, but when I open a video with SMPlayer It goes a bit laggy, not a lot, it´s ok, but the performance isn´t the same.
If I configure SMPlayer to play MPV videos in another window it works exactly like MPV videos open through SVP menu, then why if I use SMPlayer to play videos in the SMPlayer interface it gets laggy? is that because SMPlayer interface is badly optimized or something? or some configuration option that has to be in SMPlayer to rid off of the lag?.