Slow Intel 10GbE CX4 adapter behaviour

[rihad]

Problem solved, I'm so embarrassed :) The issue on 7.2 mentioned above 
with ixgbe (tons of "fragmentation failed" errors) was real. The issue 
in 8.3-RC3 was because dummynet wasn't being loaded at all... so no 
traffic could pass on it, despite dummynet_load="YES" being set in 
/boot/loader.conf. So I turned it on in /etc/rc.conf : 
dummynet_enable="YES" and loaded it "kldload dummynet" in order to do 
without a reboot. Works like a charm so far. Thanks to all!