Variable Gigabit Ethernet speed?

[MarkHaysHarris777]

I did some tests yesterday with one of my Pine 2GB boards...  I consistently only get about 33 Mbit/s to or from Pine...  For consistency - I measured also several other devices hooked up to the same Gbit switch :

1. AMD Phenom Desktop running elementary freya, consistently get approx 933 Mbit/s (intel branded Gbit NIC)
2. i7 octacore Asus laptop running Ubuntu 15.10, consistently get ~Gbit results (USB 3.0 gbit dongle - realtek chipset)
3. HP Microserver NL40 (dual core AMD) - running FreeBSD/FreeNAS, consistently get ~Gbit results (intel chipset on/board Gbit NIC)

iperf from Pine64 to / from those three hosts?  Consistently get sub-par, lower than 100 Mbit results (e.g. ~ 33 mbit/s).  This board is plugged directly into an Edimax Gbit switch (as are the other three machines).

The pine is running the latest Debian Jessie XFCE build with the hard-coded MAC address in /boot/uEnv.txt.

Also - for comparison, I have an NTC CHIP running debian jessie kernel 4.3, with an Asus branded (AXP) USB ethernet dongle, I get ~33 Mbit/s - and this host is travelling through a TPLink router, over 500 Mbit ethernet over power to get to the switch and the iperf "server" (the AMD Phenom desktop).

would you please post your results using iperf3.

Also... please take the poll on the ethernet sub-forum, and provide your data as per the instructions on the first post. Thanks, much appreciated !