già provato. Forzato a 1500 l'MTU con drtcp sulla ethernet connessa al router. Cambiato il valore nelle impostazioni del router a 1500 per MTU e MRU e a 1460 per MSS. Ebbene, ora il router anche riavviando mantiene questi valori, però speedguide continua a darmi risultati strani:

TCP options string = 020405a001010402
MTU = 1480
MTU is optimized for Windows XP PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1440
MSS is optimized for Windows XP PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 64240
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 64240

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
506880 (MSS x 44 * scale factor of 8)
253440 (MSS x 44 * scale factor of 4)
126720 (MSS x 44 * scale factor of 2)
63360 (MSS x 44)
bandwidth * delay product (Note this is not a speed test):

Your RcvWindow limits you to: 2569.6 kbps (321.2 KBytes/s) @ 200ms
Your RcvWindow limits you to: 1027.84 kbps (128.48 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON

In attesa di ispirazione per ora mi fermo. Ogni idea rimane comunque estremamente ben accetta.