This phone has been 3years ago an high end phone. What is the phone distribution here on this site? Maybe there are less powerful phones.
Mobile design is IMHO not only about the responsive layout. It is also about speed/bandwidth and hardware limitations on these devices.
- meta.discourse.org: http://www.webpagetest.org/result/160330_8K_592802ee00441a32192a5183af8ad1c9/
- try.discourse.org: http://www.webpagetest.org/result/160330_49_024ca5619286ee2c338b3254e088d574/
- forum.syncthing.org: http_://www.webpagetest.org/result/160330_YB_191aff8be451ac26636f4b115f2cc018/
You can see there is timerange with 100% cpu.
P.S. forum.syncthing is the fastest