is it normal for S4? btw my phone is rooted and running darkstalker rom.
I bet any phone will heat up under those conditions. Sounds normal.
Anything demanding on the CPU will cause the phone to heat up. Gaming, Video Chatting, GPS Navigating (GPS Nav made my iphone 4s so hot you could cook on it), even app updating if you update 20 apps at once.
I am now waiting for a poster saying their S4 never gets hot, which means little to no 3D gaming, video streaming with 4G, or GPS navigation. The magic pixie dust is STRONG with this device. Kind of like folks with the iPhone 4s and 5 saying theirs do not ever get hot and those things can get as hot as a device can without morphing into all glass. An overstatement, but fitting.
Mine can get quite hot at times. It's a little concerning, but is the nature of the beast
It will probably happen.
But I'm not really sure. I came from s2 international version and rooted phone. But ot doesnt get hot like my s4 now. Me and wife got s4 samething happened gets hot. So maybe its normal for s4.mine is rooted and hers is not yet.
How long do you video call or game before you notice the heat?
Video call and gaming??? That is a heavily load, both require both the CPU and GPU going hard, as well as Microphones, speaker, Display, Audio chip etc... The phone is bound to get warm.
Does your S2 have a quad core CPU? Does it score as high in benchmarks? Well, it has nowhere near the CPU power S4 has so it does not heat up.