Mystery - Hotspot working but not working properly, why? Android 5.0

[AC Question]

Here is the problem:

I can create hotspot by my Lenovo K3 Note model K50-t5 Android 5.0 phone and my laptop can connect to it both way - wifi or USB but the connection gets interrupted during 1) downloads 2) video calls 3) online games. One can see no problems at all when only browsing internet, watching Youtube, checking e-mails.

My friend came with his older Lenovo P 780 and made a hotspot and it worked perfectly for his and my laptop - no problems - same room and same service provider in UK and same plan. I made hotspot and connection got interrupted on my and his laptop. The question is if it is hardware, software, settings or what? The service provider is Three in UK. Apparently, P 780 runs on Android 4 and is only 3G while my phone has Android 5.0, is 3G/4G, newer and more powerful CPU and more RAM. We tried hot spots by 2 different Lenovo P 780 and both worked = flawless connection for the laptop.

Seeing that my laptop loses internet connection from the phone during 1) downloads 2) video calls 3) online games regardles of how it is connected - wifi or USB - the problem shall not be with USB or wifi. If it were wifi, USB would work and vice versa, or no? One online game with connection and ping indicator shows ping rising up to 3000 approximately every 5 minutes and then the connection is lost and page must be refreshed. Similar for video calls - just the intervals seemed to be more random.

I have tried: reset to factory; restart; switch on/off; disabling 4G; wifi or USB or both at the same time; restarting the laptop (which has had no problems with wifi connectivity so far - wireless router); ticking the option "mobile data service preferred" in the engineering mode. None of it has helped. Needless to say my phone is new with minimum apps. I have no idea what else I should do or try.

 

[B. Diddy]

Welcome to Android Central! When you're just using your phone on its own (and not as a hotspot), do you have any similar problems with unreliable mobile data?

 

[PavelT7]

Thank you. I think the answer is no - it looks the problem is only with hotspot/USB data sharing and only 1) downloads 2) video calls 3) online games. I have not tested the phone on video calls and online games but long downloads (1 hour and more) have worked on the phone. The same downloads which were interrupted on the laptop so many times that they failed to complete.

 

[B. Diddy]

One hour is a long time for a download. Is this because of slow download speeds? If the connection is slow, the computer might be timing out.

 

[PavelT7]

No, it is online game + video calls + download. The laptop had no problem with 2-3 hours download when it was connected through cable broadband and wireless router. It is something with the phone hardware - software - settings - mobile network ...something. The Lenovo P 780 could make a stable hotspot - same room, same mobile operator, same data plan, the difference is in the phone - my is newer and better model than P 780 and yet P 780 works better as for hotspot or my phone is faulty - something is wrong.