Why does skype sound slow down?

Question

Skype

Hello! Guys tell me where to dig.
There is an office for 8 cars. The Internet enters the Wi-Fi router, from it to the switch, and further from the switch, a network cable is connected to each machine. That is, 8 cars on the internet via cable.
I'm making a video call on Skype (latest version 8 desktop), everything is fine, video, sound. But if I connect to a video conference consisting of three people (including myself), video + sound, then the audio is wild brakes, the speech lags behind and is distorted. I disconnect from the conference, connect from my smartphone via Skype (Internet on smart from a Wi-Fi router, which is described above) - then everything is perfectly audible.
I opened the task manager on my computer - the processor is loaded by 60-70%, 40 of which is Skype. The network is not loaded. Internet - 80 Mb/s
Win 10 64b. Laptop (acer aspire es 15 es1-532g-p1q4) : Intel Pentium N3710 (1.6 - 2.56 GHz) / RAM 4 GB / HDD 500 GB / nVidia GeForce 920MX, 2 GB

Answer 1

You have empirically established that if you remove the switch from the chain, then everything is OK and ask what to do? I would try another switch.