Tried now my wife's i5-4200U (Intel 4400) 4GB SSD W10 Notebook
and with the Scirra test on Edge and Chrome 60fps- not a single frame dropped
So I did some more testing with a canvas test tool http://www.kevs3d.co.uk/dev/canvasmark/
Here is my i3-5010U Notebook, 4GB Ram
CanvasMark Score: 6651 (Chrome 48 on Windows)
with Edge 6850 (in some tests like 1 and 2 it is 20% faster than chrome in others 20% slower)
with Firefox 6784
Test on wife's i5-4200U (Intel 4400) 4GB SSD Notebook
Chrome 7832
Edge 7566
Test on my Gaming Rig i5-6500, 16GB, GTX 960, SSD, W10 system
CanvasMark Score: 13946 (every test was way faster than on the notebooks - especially test 5)
In Edge only 7450 (Here some test where very good, but others very low)
I checked their Twitter page and saw that it looks like this are normal test scores (but please check your computer and post your results here).
So this test gave me even more questions
1. The gaming rig has a high score but with the Scirra test a lot of dropped frames
2. my wife's computer doesn't drop any frames