Hi, just want to add my story here, as i had this very issue just yesterday, after i bought msfs (steam).
I live in Vienna, have a 110MBit connection and never ever had any issues of slow downloading.
So i did the purchase in steam and then steam downloaded the initial MSFS installer (about 1,7GB), with full speed of course.
After starting MSFS, creating the acocunt it told me what was needed to dl and so i sait yes, start it.
About the first 10mins went well, nearly full speed, but then it started to get choppy. It was no constant stream anymore and more and more pauses interrupted the downstream (my connection was not loaded by any other thing).
This was getting worse and worse and ended in 5secs pause, then 2 secs with 5MBit (!) and 5secs pause again and so on…
I googled and found threads about this among this one.
I tried most of the stuff mentioned in these threads but to no avail.
Then, today i tried one more thing out of desperation:
One here mentioned to try to set the “netsh int tcp set global autotuninglevel=normal” to disabled and then to normal again, this didn’t help either in my case. But I looked at the option this setting has and found that there is also a setting named experimental and I tried this.
netsh int tcp set global autotuninglevel=experimental
(with “netsh int tcp set global” one can see the available otions).
I still can’t believe it to some degree but this actually seemed to have cured my issue. With this setting I’m currently downloading since 40 minutes an have constant, choppyfree 110 MBit…
I don’t exactly know what this setting does in general, but it somehow must be related on how a windows app handles traffic. Again, I never ever had slow download in steam or any other source from where i downloaded stuff (e.g. xplane).
So, if all of the above doesn’t work for you, you can add this to the try list, its worth a shot.