Blondie
Il provider non credo sia la causa, io in questo momento in IPoE con scheda di rete 2.5G saturo regolarmente la banda (MTU 1440) :
C:\Windows\system32>speedtest -s1434
Speedtest by Ookla
Server: CPN - Milan (id: 1434)
ISP: Revolution Provider Srl
Idle Latency: 8.91 ms (jitter: 0.07ms, low: 8.74ms, high: 8.97ms)
Download: 2368.34 Mbps (data used: 2.4 GB)
22.28 ms (jitter: 0.89ms, low: 6.94ms, high: 29.39ms)
Upload: 2261.58 Mbps (data used: 1.8 GB)
7.82 ms (jitter: 0.36ms, low: 7.06ms, high: 11.05ms)
Packet Loss: 0.0%
Result URL: https://www.speedtest.net/result/c/19d7566d-c60c-4772-bfe0-a65725fab57c
C:\Windows\system32>speedtest -s45809
Speedtest by Ookla
Server: i3D.net - Milan (id: 45809)
ISP: Revolution Provider Srl
Idle Latency: 6.84 ms (jitter: 0.14ms, low: 6.59ms, high: 7.01ms)
Download: 2369.97 Mbps (data used: 2.3 GB)
22.72 ms (jitter: 0.92ms, low: 7.56ms, high: 24.75ms)
Upload: 2178.59 Mbps (data used: 1.9 GB)
8.94 ms (jitter: 0.24ms, low: 8.23ms, high: 9.70ms)
Packet Loss: 0.0%
Result URL: https://www.speedtest.net/result/c/b9aa88da-52d5-4676-9ca3-e18b12abba4d
C:\Windows\system32>speedtest -s38731
Speedtest by Ookla
Server: Fiberwide S.p.A. - Milan (id: 38731)
ISP: Revolution Provider Srl
Idle Latency: 7.47 ms (jitter: 0.10ms, low: 7.40ms, high: 7.62ms)
Download: 2368.93 Mbps (data used: 2.4 GB)
24.44 ms (jitter: 0.98ms, low: 9.10ms, high: 26.21ms)
Upload: 2113.49 Mbps (data used: 2.2 GB)
7.15 ms (jitter: 0.27ms, low: 6.34ms, high: 8.04ms)
Packet Loss: 0.0%
Result URL: https://www.speedtest.net/result/c/cf157e0f-5730-4f6d-9426-961a14cef2fe
C:\Windows\system32>speedtest -s59135
Speedtest by Ookla
Server: Grain Connect - Manchester (id: 59135)
ISP: Revolution Provider Srl
Idle Latency: 37.41 ms (jitter: 0.09ms, low: 37.38ms, high: 37.52ms)
Download: 2367.55 Mbps (data used: 3.1 GB)
52.79 ms (jitter: 1.90ms, low: 38.11ms, high: 83.08ms)
Upload: 2205.40 Mbps (data used: 2.3 GB)
38.43 ms (jitter: 2.10ms, low: 37.39ms, high: 55.18ms)
Packet Loss: 0.0%
Result URL: https://www.speedtest.net/result/c/ea6d50ff-10ef-4699-a011-6df7b7c5337f
Che ONT ti hanno dato esattamente?
Hai provato anche da altri PC\dispositivi cablati?
Se disabiliti il "flow control" dalla scheda di rete cambia qualcosa?