I’ve been testing my network speed again, trying to figure out why I’m not really seeing gigabit speeds.

I’ve eliminated the switches from being the problem as using a bit of crossover between two PC’s made no difference at all.

I think its a either a limitation of the RTL8169 cards or the PCI bus, as I tried from the Pentium4’s built-in Intel Pro 1000CT and speeds from iperf went up from about 67MB/s to about 82MB/s – although that was still to another RTL8169 PCI card on the other end. I tried a combination of “pv < /dev/zero | nc -u 5000" and “nc -u -l 5000 > /dev/null” to create a client/server pair with no filesystem access, and was getting similar results to iperf.

I was considering making the Pentium4 into the fileserver, although it seems like extreme overkill to have a 3GHz/3Gb machine serving files to XBoxes etc for 15-20MB/s difference, plus its a bit of a noisey box in comparison to the Athlon 2.4GHz/1.5Gb.

I guess 67-82MB/s is not bad without jumbo frames enabled, as the maximum would be about 119MB/s with a 9k MTU – which wouldn’t work with the 100Mbit routers, printserver and XBoxes.

I’ve also turned off hard disk spindown (hopefully it has worked) on the fileserver, as that causes quite a nasty hang of Nautilus whilst the NFS server is figuring out why it can’t read from the disk: “hdparm -S0 /dev/sda”, plus it’s probably killing the disks spinning up/down all the time.