We made some tests on Windows 10 PC (i5-8250U 4 physical cores, 20 Mb RAM) playing 25 streams (360p 25 fps, bitrate 1,5-3 Mbps) in 3 Chrome tabs. During the tests CPU load were in range 40-50 % (25% GPU load), without noticeable freezes or stream visual degradation.
So WebRTC playback capacity...