99% of Xbox games are served by the players so there are no Xbox servers as such in relation to game play connection issues.
Even though you've tested on that Madrid server you are still getting the 1.73 Mb DL and B rated ping.
HOWEVER. Your own router diagnostic which is where you are getting the line rate. That seems to be saying that you are getting a 20 Mb DL speed which is pretty high and certainly not 1.73Mb.
I have a feeling it is something to do with your ISP possibly capping your limit.
I had the exact same thing with BT in the UK. I tried those websites and a few other online testers.
I kept getting the same results of 0.35 Mbps DL.
BT from their end and from a router check like your's were telling us that we were getting 7 - 8 MB DL.
They seemed to think that the test at their end which was the same as the diagnostic test at our end on their modem / router diagnostic was confirming we were actually getting 7- 8.
It was obvious we weren't due to how badly the connection was performing (couldn't even stream a simple video on Youtube, Xbox live lag everywhere, 10x worse that out previous connection, normal internet browsing almost impossible etc). This was further
clarified by all the independant checks I did that we weren't getting what they said.
This really showed that their diagnostic of info coming to the house was possibly true. If that's the way it works (measuring only up until the point it hits the house)
and
The diagnostic on the router was totally wrong. My assumption is that it only measured how much WE SHOULD be getting by contacting directly to BT's incorrect diagnostic.
At the end of the day the issue was resolved and it was caused by the ADSL capping our limit.
Basically. Previous provider connection DL was around 2 - 4Mb so we knew our line could handle that.
We had pretty old wiring and some noise on the line.
BT's ADSL detected this small noise as a possible issue.
It capped us at 0.35 MBPS.
Even though we knew we could get 2 - 4 DL from the previous provider.
BT were stating they think we should be getting up to 7 - 8.
They sent an engineer. Replaced a box on the wall and some wires. That removed the noise.
The ADSL reconfigured and gave us the true amount instead of restricting us way too low purely as it had this "noise" issue.
It seems, at least with BT, that the ADSL if encountering ANY kind of problem will restrict to a way too low level.
TBH with ADSL providers having to share the bandwidth in this country / competition etc I think they will just ignore it until you cause a fuss. Maybe I'm too much of a conspiracy theorist. There is something a bit fishy seeming about this as it seems quite
common with ADSL providers now in conjunction with growing demand. Certainly here in the UK. It's about managing available bandwidth and profit margins it seems sometimes. Due to maximum capacities anywhere and the way ADSL works there is a chance there are
similar goings on in any country where people are using ADSL.
At the end of the day laying fibre optic cable infrastructure is a lot more expensive that providing ADSL on existant copper wiring. Cable is the way forward TBH.
I miss my old flawless10meg Cable connection.
My bud who suffered for 6 months was with Sky. With my changing provider and having issues, I mentioned the slow Youtube thing. He got that too. He also couldn't stream dashboard vids, internet slow, Xbox laggy etc.
He's no techy at all. Turns out Sky were capping his ADSL as well but due to his lack of understanding this sort of thing he had thought it was just the norm. Oddly enough he is in a new build where there should be no line or noise issues.
I believe they've since corrected his issue and might have given him some discounts / refunds / extra services or something. I'll have to ask him.
Sorry. I'm ranting / waffling again.
Good luck in your findings.