If you face lag in Videos while playing them on VLC then you can take help of your GPU under some circumstances to boost playback. Actually your graphic card can process some data and reduce the load on your processor.
But VLC does decoding in GPU at the decoding stage only and then gets the data back to go to the other stages (streaming, filtering or plug any video output after that).
What that means is that, compared to some other implementation, GPU decoding in VLC can be slower because it needs to get the data back from the GPU. But you can plug ANY video output (sink) to it and use all the VLC video filters.
So lets get it work :-
Launch VLC and press Ctrl+P to bring your Preference option box
Switch to Simple View option,
Now navigate to Input & Codecs and then check option saying Use GPU accelerated decoding