Google's Project Stream partners with M-Lab and is a garbage test. It has, from what I have personally experienced and read about, no bearing on how well Stadia will work for you.
I get over 300 Mbps on any other speed test, and Stadia works perfectly for me, but on the one Google uses I barely get past 10 Mbps. In Stadia itself my connection is rated as "Excellent" when using my Chromecast Ultra.
It is unclear to me whether you are actually having issues, or whether your issue is that test gives poor results. If it is the latter, ignore it. If it is the former, let us know more details so we can help.
@williamthrill @Sornin : Correct, the M-Lab servers that are part of the project stream test as far as I can tell are nowhere near to the actual Stadia servers themselves. Or if they are, then the last stretch between those M-Lab servers and the Stadia servers is in a bad state.
I suspect that the M-Lab servers aren't actually at fault, either they don't have enough of them deployed yet, or they're deployed in all the wrong places, or the metrics that are supposed to be measured aren't worth a penny.
So, in the case of the 3mbps vs 200mbps scenario, I suspect that that there is some maintenance work on the Google infrastructure that is causing this performance hit to the Stadia servers, it shouldn't be as bad as that ever, unless they're doing some break-fix work on stuff.
That it worked fine for you in the past and now doesn't also points to infrastructure changes IMHO. If you're getting good consistent speeds reported by a range of different speed test tools (in the UK, I tend to use speedtest.net, fast.com) and then take their measurements with a pinch of salt, they may not always be terribly accurate or consistent.. LOL
fast.com - 670 Mbps
speedtest.net - 550.65 Mbps
projectstream - 347.76 Mbps
After that you can raise a case with Stadia support, and endure level 1 support passing the blame of the issue to you, your ISP, your street cabinet, your WiFi, your next door neighbors WiFi, sunspots, the amount of pollution in the atmosphere, heck they may even try to blame Donald Trump and Greta Thunberg. But from past experience they certainly won't blame the magical Google network.
As was the case with some German users recently, there were so many of them complaining, that eventually got a response from Google, but only after the issue was resolved, and that was just to thank folks for their patience. So, it really does depend on how many users are getting affected and how loud you can make yourselves heard as to whether or not you'll make any progress. It might be just easier to roll over and wait until they fix whatever it is that they're doing, and if it hasn't resolved itself in a day or two, try shaking the support tree some more....
If your details are correct you internet is not that great unfortunately, 25ms latency is quite high for stadia but it should be ok if you use gamepad.
Check this for more info, there is a lot of useful information:
https://www.reddit.com/r/Stadia/comments/e9g65l/bandwidth_latency_cpu_performance_analysis/