gigabit network, 350mbit/s what is this rubbish?
I've installed a new switch last week, upgraded from old netgear layer 1 hub 10/100 8 port to a new D-Link DGS-1024D 10/100/1000Mbps 24-Port.
I've been doing throughput test using iperf on Gigabit capable machine, and all of them can only do about 300-350 Mbits and just so we're clear, that's 300 Megabits. I've check the connection and settings and all of them are at 1000, full duplex. I've also tried tweaking sysctl on the centos boxes, and trying all kinds of configs and none of them have any effect on them. It's like They are stuck at 300Mbits. I've tried four different machines and with the same result. I've tried direct connection via a crossover cable taking the switch out of the equation and it still has the same effect.
For some weird reason one additional computer *totaling 5 computers with gigabit cards* can allow 400Mbits coming in from "certain computers" but going out to any other machine it's 300Mbits and this is an old Tbird clocked at 933 and 4 ide drives in raid 0 and two 5400 U160 scsi drives also in raid 0.
The cabling is sub par in the home but most of my test have been conducted on good Cat5e, I have cat6 bulk cabling in a box have not gotten around to making some cables.
Am I missing something? Why are we going around 300Mbits when I was kind of expecting 500-600Mbits, is this the sad truth of Gigabit?