Windows 10 throttles internet download speed. Wonky built-in settings?

Windows 10 appears to throttle internet speed.

The link tested is
http://sfo-korg-mirror.kernel.org/op...DVD-x86_64.iso

It will start out at 20MB/s, then throttle down to just 200KB/s. !!!! It will sit at this superslow speed for a while, then climb up later, only to throttle down super slow again.
This is a dedicated server on a gigabit line.

At home, my 100mbps line holds the download steady at 100mbps. No speed dip.

I know very little about how Windows controls transfer speeds, but I have read about Windows auto adjusting the tcp window and such.

It seems the netsh settings are helping and hurting.


Also, I have 10mbps upload speed at home, and when I try to upload to my 1gbps server, the speed is throttled at 1.5mbps.
It starts at 10mbps, then quickly throttles.


Whatever is working behind the scenes seems to be contributing to the server's slow download speed, and my slow upload from home.

If I disable auto-tuning, speeds are even worse.
The http server goes from maxing out my 100mbps line, to <10mbps.
So outbound speeds from the server suffer, and inbound speeds to the server still suffer.


help ?!

Windows is not throttling anything. You are trying to download an iso on a server that can be shared with other websites and also be bogged down by multiple people attempting to download files. Without knowing where that server is and how many other servers are shared in a VM, all of that is factored in in that the person who set it up had to implement some kind of QOS to keep a single user from eating up all of the available bandwidth.

it's most definitely Windows, because I have another Win7 server in the same data center that can sustain 20MB/s downloading that file, either simultaneously, or right after.
That linux.iso download server has lots of bandwidth.

Somehow, windows is screwing up the tcp settings on the fly. There's no reason the windows server should be capping my upload speed to it at 1.5mbps, especially on a 1gbps server.

Also, when I run linux live CD on the Windows 10 server PC, I am not capped at 1.5mbps. I can upload to the linux at my max upload 12mbps.

So it's definitely a tcp setting in Win10. I even tried Win7, and it's the same problem.
Windows caps my speed from home>>> server

I'm 2500 miles away, so I have 90ms ping.
The win10 server does not cap the speed for transfers from closer locations.
It's definitely miscalculating the optimal transfer speed

link626 said:

it's most definitely Windows, because I have another server in the same data center that can sustain 20MB/s downloading that file, either simultaneously, or right after.
That .iso download server has lots of bandwidth.

Somehow, windows is screwing up the tcp settings on the fly. There's no reason it should be capping my upload speed to it at 1.5mbps, especially on a 1gbps server.

What's the other server running?

BTW: Besides the throttling thing, I have found Windows uses a lot more bandwith for whatever (didn't bother wiresharking) - when I was on a capped plan, I switched to Linux for internet stuff...

link626 said:

The autotuning is f'd up

Hmmm... maybe due to BITS which has QOS built in that'd f'd... I'll be interested in what the network guru's think...

What are the two IP's of both computers that you are running Windows desktop as a server, which is not going to work as you want. If you are going to run a server to host files, you really need to be using Linux and have it set up as a FTP server with strong security.

Yes Windows 7 and 10 have different QOS schemes. A ping of 90 means that you have a lot of hops and that distance of over 2500 miles is going to be an issue. Windows adjusts up and down speeds depending on congestion along the way and the size of the packets being sent, which can vary in size and if there is a CRC error, it has to retransmit the packets that were malformed.

Superfly said:

Hmmm... maybe due to BITS which has QOS built in that'd f'd... I'll be interested in what the network guru's think...

If the OP is using Windows Desktop, they are always going to have a issue. Especially if they have different computer hardware and not using a VM like most people do. With it being over 2500 miles away, the OP is going to see problems.

link626 said:

If there were only a way to turn off autotuning and adjust tcp for best performance.

Look at this: SpeedGuide.net :: TCP Optimizer / Downloads

Also, you should remove all network protocols and disable all features, you do not need.