Wysoka szybkość limitów ping i utraty pakietów

Mam problem z bolesną niską prędkością internetu na moim Air 11 ”pod koniec 2010 roku w Sierra 10.12.2. Ani mój telefon, ani inne komputery użytkowników w sieci nie mają tego problemu. Przed wystąpieniem tego problemu użyłem oficjalny adapter kabla sieciowego.

Próbowałem już zrestartować komputer w trybie awaryjnym, odtworzyć interfejs Wi-Fi. Dla ilustracji mam

PING google.com (172.217.29.46): 56 data bytes
Request timeout for icmp_seq 0
64 bytes from 172.217.29.46: icmp_seq=1 ttl=56 time=17.265 ms
Request timeout for icmp_seq 2
64 bytes from 172.217.29.46: icmp_seq=3 ttl=56 time=26.402 ms
64 bytes from 172.217.29.46: icmp_seq=4 ttl=56 time=9.201 ms
Request timeout for icmp_seq 5
64 bytes from 172.217.29.46: icmp_seq=6 ttl=56 time=18.831 ms
Request timeout for icmp_seq 7
Request timeout for icmp_seq 8
64 bytes from 172.217.29.46: icmp_seq=9 ttl=56 time=27.363 ms
64 bytes from 172.217.29.46: icmp_seq=10 ttl=56 time=7.736 ms
Request timeout for icmp_seq 11
Request timeout for icmp_seq 12
64 bytes from 172.217.29.46: icmp_seq=13 ttl=56 time=21.891 ms
Request timeout for icmp_seq 14
64 bytes from 172.217.29.46: icmp_seq=15 ttl=56 time=10.362 ms
64 bytes from 172.217.29.46: icmp_seq=16 ttl=56 time=14.790 ms
64 bytes from 172.217.29.46: icmp_seq=17 ttl=56 time=21.166 ms
64 bytes from 172.217.29.46: icmp_seq=18 ttl=56 time=11.302 ms
64 bytes from 172.217.29.46: icmp_seq=19 ttl=56 time=16.252 ms
64 bytes from 172.217.29.46: icmp_seq=20 ttl=56 time=6.880 ms
64 bytes from 172.217.29.46: icmp_seq=21 ttl=56 time=13.668 ms
64 bytes from 172.217.29.46: icmp_seq=22 ttl=56 time=9.033 ms
64 bytes from 172.217.29.46: icmp_seq=23 ttl=56 time=25.206 ms
64 bytes from 172.217.29.46: icmp_seq=24 ttl=56 time=10.746 ms
64 bytes from 172.217.29.46: icmp_seq=25 ttl=56 time=11.445 ms
64 bytes from 172.217.29.46: icmp_seq=26 ttl=56 time=7.018 ms
64 bytes from 172.217.29.46: icmp_seq=27 ttl=56 time=15.381 ms
64 bytes from 172.217.29.46: icmp_seq=28 ttl=56 time=6.940 ms
64 bytes from 172.217.29.46: icmp_seq=29 ttl=56 time=9.572 ms
64 bytes from 172.217.29.46: icmp_seq=30 ttl=56 time=13.075 ms
64 bytes from 172.217.29.46: icmp_seq=31 ttl=56 time=10.607 ms
64 bytes from 172.217.29.46: icmp_seq=32 ttl=56 time=18.697 ms
Request timeout for icmp_seq 33
64 bytes from 172.217.29.46: icmp_seq=34 ttl=56 time=16.847 ms
64 bytes from 172.217.29.46: icmp_seq=35 ttl=56 time=16.268 ms
64 bytes from 172.217.29.46: icmp_seq=36 ttl=56 time=11.843 ms
Request timeout for icmp_seq 37
Request timeout for icmp_seq 38
Request timeout for icmp_seq 39
64 bytes from 172.217.29.46: icmp_seq=40 ttl=56 time=12.897 ms
Request timeout for icmp_seq 41
64 bytes from 172.217.29.46: icmp_seq=42 ttl=56 time=12.243 ms
Request timeout for icmp_seq 43
^C
--- google.com ping statistics ---
45 packets transmitted, 30 packets received, 33.3% packet loss
round-trip min/avg/max/stddev = 6.880/14.364/27.363/5.655 ms

Z Facebooka:

PING facebook.com (157.240.12.35): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
64 bytes from 157.240.12.35: icmp_seq=2 ttl=56 time=29.464 ms
64 bytes from 157.240.12.35: icmp_seq=3 ttl=56 time=23.190 ms
64 bytes from 157.240.12.35: icmp_seq=4 ttl=56 time=14.754 ms
64 bytes from 157.240.12.35: icmp_seq=5 ttl=56 time=21.304 ms
64 bytes from 157.240.12.35: icmp_seq=6 ttl=56 time=21.721 ms
64 bytes from 157.240.12.35: icmp_seq=7 ttl=56 time=14.804 ms
Request timeout for icmp_seq 8
Request timeout for icmp_seq 9
Request timeout for icmp_seq 10
64 bytes from 157.240.12.35: icmp_seq=11 ttl=56 time=24.932 ms
^C
--- facebook.com ping statistics ---
12 packets transmitted, 7 packets received, 41.7% packet loss
round-trip min/avg/max/stddev = 14.754/21.453/29.464/4.906 ms