Obihai110 slowing down Internet... even when it is turned off.

[ratatatatatatatatatatata]

I bought one for my sister and she started complaining that it was killing her internet speed.
I was skeptical at first but the result was weird.

I tested the internet speed with speedtest.net and numion.com (very popular in the 90's, and still functional)

With the ObiHai110 powered on and connected to the router, it was 0.60Mbps to 0.80Mbps max.

Now the weird part is that I started testing it with the power OUT, but with the ethernet cable STILL PLUGGED IN to the ObiHai110. The results were 0.60Mbps to 0.80Mbps. At first I thought that my sister was just bitching, and that her internet speed was just slow... and that the Obihai110 slowing her internet down was just a placebo effect in her mind... but then I had the crazy hunch of unplugging the ethernet cable as well from the Obihai110... and Boom, the internet speed jumped all the way to 1.30Mbps!

This was weird so I retested it several times, and it's been throwing consistent results.
The Internet without the Obihai110 was throwing a consistent 1.30-1.36 Mbps.
The Internet speed with just the ethernet cable connected to the Obihai110 (even with the power out) was slowing it down almost 500kbps to 600kbps.

Btw, those hurrying to tell me to make it 100mb/s full duplex , I already did it and there isn't a single noticeable effect.
To help to replicate the problem, my current hardware is:
Obihai110
Wifi Router: TP-Link, model TL-WR841ND
Connected to an ADSL Modem (Router Pirelli Discus DRG A112 / BCM96338 ADSL Router)

[giqcass]

A device with no power should not have an effect on you internet speed.  The OBi does not have a battery.  There must be some kind of problem with the router or wiring.  I would be curious if you have a similar problem no matter what is plugged into the other port or if the cable you used to plug the OBi into the router is somehow messed up.

[ratatatatatatatatatatata]

@giqcass The cable being messed up shouldn't matter either, it shouldn't affect the overall internet speed.
Just to satisfy your curiosity I already tried changing ports, cables and devices, and the problem is only replicated with the ObiHai110.
One of the potential explanations would have been the half-duplexing problem that some routers seem to have, as it's been reported in these forums previously. But that possibility is already dead since I full-duplexed my ObiHai110 as previously stated.

But an unpowered device should be as good as a disconnected device... or am I missing anything here?
All the tests are still consistent: unpowered obihai110 keeps sucking around 500kbps speed away with the ethernet cable on.
There isn't a clear correlation with latency though, but with the speed it's dead clear.

[QBZappy]

ratatatatatatatatatatata

Not sure if if it is relevant, the router has  IP QoS. Perhaps disabling it will help.

http://www.pirellibroadband.com/en_IT/browser/attachments/pdf/PirelliDRGA112.pdf

[giqcass]

If you don't want to read a long rant skip to the last few bold lines.

When powered on I believe the OBi could cause you internet connection to slow however.....
If the device has no power it doesn't matter what the settings are.  Your problem has left me a little "half duplexed".  I am a certified computer tech and I understand network topology.  A router is a semi-smart device. It needs a valid response before it sends traffic over the net.   There is no battery in the OBi and even if you assume the capacitors retained some charge it would be depleted in seconds if the device was still attempting a connection.  The router you are using doesn't support POE and neither does the OBi.  Any kind of dumb connection (like a short) should just be ignored.  You are correct that a faulty cable should not be capable of causing this type of problem by itself.  I was thinking a faulty router connected to a faulty cable could possibly produce some sort of effect.  It's probably some feature on the router like flood detection causing the problem.  

When the Obi is connected to the router and powered down is there a light on for the port it is connected to?  If there isn't that means the router does not even know the OBi exists.  If the light is not blinking it means the router knows the OBi is there but it is not communicating with the rest of the network. Therefore the problem exist elsewhere.