For my experience, MiamiDX is slow. Here are some network speed results which I made when MorphOS 2.x was released: http://jpv.wmhost.com/tcpip-test.txt

And MorphOS has never been slow with net on my machines (Peg1, Mac mini 1.42 and 1.5, PowerBook). I don't know why some people have it that slow :/ And I've been using these machines with at least three operators and half dozen routers/switches. Always fast.

I made quick test now with 1.5GHz mini and PB in my current network environment... in LAN with smbfs I got 9.5MB/s with PB and 10MB/s with mini. And max 800kB/s from internet with OWB.