Also if you have multicore CPU (or one with
Intel Hyper-Threading), you can lower the FFMPEG thread count. To do this go to Tools -> Preferences (Show settings: All), then Input / Codecs -> Video codecs -> FFmpeg, then locate Threads, and set it to 4 (or to 2, or to 1). Remember to press Save to save VLC settings and restart VLC after that to make sure changes are enabled.