Background Image Not Staying Fixed

Hi. I am having trouble in setting my background image to stay fixed on these 2 pages.
Page 1: http://www.arimednow.com/?page_id=5116
Page 2: http://www.arimednow.com/?page_id=5121

In the Visual Composer settings, I have placed
background-attachment:fixed;
but the page doesn’t display correctly.

What I have noticed is that the pages display fine on Internet Explorer but on Google Chrome, the background image messes up. It displays on the page at first but when the user scrolls down, the background image either moves with the page in a very visible slow motion or the image just stays in its original position and it looks like you’re scrolling past an image element on the page. Please help me fix this. I have labeled images attached on this post to demonstrate what I mean.