In recent past releases there was a noticeable improvement to SMP related networking bits.

Does anyone have benchmarks between 8.0 and previous releases in that department?

Phoronix do test BSDs from time to time. But for different reasons I think OpenBSd missed twice. I hope to see the performance gap being close enough we can stop thinking it is very slow.

Here are some.

http://bluhm.genua.de/test.html