Pixel Shader effect on Media Element - Using GPU cycles when Paused?

Hi all,
If I apply a Pixel Shader effect to a Media Element will the shader continue to use GPU cycles if the Media Element video is paused or stopped? Just wondering if I should set the Media Element Effect to null when the element is not not in use. I have read that Pixel Shaders use GPU instead of CPU so I'm making that assumption. And it seems to generate noticable heat increase when the Shader  effect is used.

Any advice from you experts?