Bad performance on mobile

[marcelomiura]

I have a website that displays a list of items. Each item need has a countdown.
I'm experiencing some performance issues when trying to using it on the mobile devices. When I open the header navbar, which pushes the content down, sometimes the UI gets blocked.
When there a few items on the page, there's no issue. I've tried to solve the issue paginating the list, but my client need all items on the same page.
It also happens when accessing the demo page (http://siddii.github.io/angular-timer/). When scrolling the content down and up and clicking on the navbar.

angular-times: 1.3.4
angular: 1.4.14
mobile SO: Tested on several Android and iOS devices

Any ideas?