The laptops are: i7-3517U with realtek ALC269VB audio chip i7-6500U (I don't have access to this one right now, but it was a Asus ZenBook flip -- on this one

The laptops are: i7-3517U with realtek ALC269VB audio chip i7-6500U (I don't have access to this one right now, but it was a Asus ZenBook flip -- on this one I've definitely seen 15%+ usage by PulseAudio during video calls.) i5-7200U with conexant CX8200 The latest desktop is: Ryzen 5 2600 with realtek ALC887-VD (on this one the CPU load was lower than on the others, but still there)