Im running HS in windowed mode on an asus laptop. Im using chrome browser and if I start a video on youtube it causes the game to freeze in weird way. I can still hear the sound and interact with the game but i cant see what Im doing. The in game screen is frozen and i cant see the mouse pointer. It only happens when im in game. If Im just hanging out in the lobby i got no issues.
Most things have their limitations…your laptop seems to have reached one. My personal guess(es): memory, modem/router bandwidth, or graphics issues.
Open your Task Manager. Resources tab. Keep that open, then duplicate what you were doing before. Watch the graphs, see what spikes when you try to load/run both programs.