Choppy scrolling with "background-attachment: fixed" - css

Question

I'm having issues with background-attachment: fixed. When I apply it to the elements on my page it creates a very choppy scrolling effect. Essentially not something that is not a good experience for the user.
My code is here:
HTML
<div class="con row1">
<p>Some text here just to flesh out example</p>
</div>
<div class="grad-space">
</div>
<div class="con row2">
<p>Some text here just to flesh out example</p>
</div>
CSS
.con {
height: 100vh; }
.grad-space {
height: 50vh; }
.row1 {
background: url('https://s-media-cache- ak0.pinimg.com/736x/3d/88/09/3d880927ac8bfec60a04ca93064569e0.jpg') no-repeat center;
background-size: cover;
background-attachment: fixed; }
.row2 {
background: url('https://d3rt1990lpmkn.cloudfront.net/640/31762579d8fd04a756fb791ac9c3634b5828f0dd') no-repeat center;
background-size: cover;
background-attachment: fixed; }
Here's a link to the codepen showing exactly what I'm talking about:
http://codepen.io/reskk/pen/qaYJwq
Edit: Fullpage Codepen: http://codepen.io/reskk/full/qaYJwq/
Now strangely enough when I resize the browser down to a small width (say 800px) the scrolling actually becomes very smooth - just as you'd want it to appear on a finished project.
When the browser is at its max width (and max height, which you can't quite fully get on codepen due to to the code-input box) that is where the janky, choppy scrolling happens.
I've done extensive searching on this and haven't been able to find a solution.
Does anyone have any ideas on this? It's such a gorgeous effect but is unfortunately made useless by the performance it yields.
Thanks,
Reskk

Answer 1

You know you can see any codepen in full page? Fullpage Codepen
About your choppy effect, what you probably are looking is a scroll animation smoother, not sure if this is the right term. What it does is that delays the mouse scroll effect, or reduces "line jumps" height, making the movement look better.
CSS Parallax by davidwalsh
Edit removed frameworks/libraries references (offtopic)

Answer 2

I was stressing with the same problem, and found a lovely solution here: https://medium.com/vehikl-news/fixed-background-image-performance-issue-6b7d9e2dbc55
Essentially, you need to remove the background image from your .rows and move it to a :before element for each. That way you're not using background-position: fixed, but rather position: fixed on your pseudo element.
.hero {
min-height: 100%;
position: relative;
overflow: hidden;
&::before {
background-image: url('background-image.png');
background-repeat: no-repeat;
background-position: center top;
background-size: cover;
content: '';
height: 100%;
left: 0;
position: fixed;
top: 0;
width: 100%;
will-change: transform;
z-index: -1;
}