Download behaviour steam client on Windows

[Dirty&Hairy]

Hi,

I was downloading a large file in the browser and then also started downloading a large game update in Steam.

Steam grabbed the entire bandwidth and only after the game update was finished, the download in the browser was fast again.

This was not a problem, however I would assume, that Windows equaly distributes the available bandwidth between the applications. How does Steam grant itself so much priority?

As I said: not a problem I am just curious.

[NakiBest]

It is your WiFi router and/or ISP that does that, not Steam client. :)

On some routers, you could change it a bit via the router Admin Panel Prioritization settings (if any).

[Dirty&Hairy]

Thanks for the reply!

I am a network engineer and have my network at home fully under control. However my expertise of the Windows network stack is not that deep.
From the point of view of my router it is the same client and I have no QoS for Steam configured neither on the edge router nor the Wifi/Switch level. I hardly believe my ISP prefers the Steam CDN over the Ubuntu one. Thats would even be illegal, I think (net neutrality).

Actualy I thought that Windows has some kind of QoS I never heard of and Steam makes it self priority there. Is that possible?

[cSg|mc-Hotsauce]

Steam will try to saturate your connection unless you throttle downloads in the Settings.

[aiusepsi]

Steam parallelises downloads by using multiple TCP connections to multiple servers when downloading. Each TCP connection should get a roughly equivalent share of available bandwidth*, so Steam using multiple TCP connections is going to get more bandwidth than your browser using only 1.

* TCP congestion control works by throttling each TCP connection individually when packet loss is detected on that connection, i.e. when your ISP drops packets that are being sent to you because there's insufficient bandwidth to send them all to you. It should be effectively random which packets are dropped, so the overall effect should be that each TCP connection is throttled to the same level.

[Dirty&Hairy]

Tha makes a lot of sense. Thanks a lot

[Elucidator]

Some NICs come with software that attempt to regulate download streams by identifying the program requesting them. (Killer NICs software has this for example).

Some more modern routers with fancy features can also achieve it indeed, but at any rate, there is a reason why you can limit the amount of mbits on your bandwidth steam is allowed to use. Simply make sure there is bandwidth left and your other download can also happen at the same time.

"However"
This does not advance the downloads faster. When both downloads happen at the same time, they will clear at the same time.
When you prioritize one, one is cleared before the other.

but either way, in both cases, both downloads take the same amount of time to complete in total. So, I don't think it matters unless you don't mind waiting longer and want to watch youtube or netflix basically.

[NakiBest]

Okay, have you tried to use a speed downloader instead of just your WIndows web browser?
This one is nice:
https://www.internetdownloadmanager.com/
but there are others too.

I am curious how the speed will change if you use Steam PC client download along with downloading that large file via IDM or similar program. :)

EDIT: Also, how large is that large file? Is it an ISO file? :)