I’m going to work up a thorough review soon, but preliminary testing confirms what others have seen: Bi-directional performance of the ER-X is sub-1Gb/s aggregate and a fair bit lower than uni-directional performance. I’m seeing over 900 Mb/s uni and low 700 Mb/s for bi-directional NAT’d traffic on v1.9.1.1.

I’ll do more testing with routed non-NAT traffic next week.

I’m surprised more attention hasn’t been brought to this given how often the ER-X is promoted as a cheap router for Google Fiber and other Gigabit FTTH offerings. The reality of the ER-X is that it’s more like a 350/350 router than Gigabit. 

In trying to understand why this is, I came across a blog entry speculating that one of the 1Gb/s interfaces from the SoC is reserved for the SFP on the ER-X-SFP. I’ll be swapping one of these ER-X’s for the ER-X-SFP at my girlfriend’s home to test if there’s a performance improvement using eth0 and eth5 on the ER-X-SFP vs eth0 and eth1 on the ER-X.

Another item of note: Pass-through PoE does not require a 24v PSU! The included 12v PSU is only 0.5A and not suited to powering anything else — it will, but expect stability problems under load, or perhaps a fire — but any 9v-26v PSU that supplies more watts will work. An upgraded 12v PSU will generally be a few bucks cheaper than 24v.