looks like a problem with my chromium as firefox is almost idle when displaying the indicators.
(30.0.1599.114 Developer Build 30.0.1599.114-0ubuntu0.12.04.3 x86_64)
It works fine on Safari on my iPhone 4.
I am on 31.0.1650.63-0ubuntu0.13.04.1~20131204.1, and it was ok here. CPU around 3-4% for most of them. One of them was 8%.