Struggling With Low Speeds < 15MBps Over Gigabit

StephenB wrote:
-In addition, please confirm that jumbo frames are actually working on your network.

I initially tried the 8960 value you mentioned and sure, I got the message 'Packet needs to be fragmented but DF set'.

I kept trying different values until I reached 1449.

It was at this point I got the following:

Pinging 192.168.1.2 with 1449 bytes of data: Reply from 192.168.1.2: bytes=1449 time<1ms TTL=64 Reply from 192.168.1.2: bytes=1449 time<1ms TTL=64 Reply from 192.168.1.2: bytes=1449 time<1ms TTL=64 Reply from 192.168.1.2: bytes=1449 time<1ms TTL=64 Ping statistics for 192.168.1.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

When I tried 1450 or anything higher as the value, I got the 'Packet needs to be fragmented but DF set' message again.

As for cables, all are at least CAT5e with the odd CAT6 in the mix.