Steam Download Speed

[Freebird Goblin]

Just wondering if it is normal for once you begin a download on steam the download speed is really high (100 mbps for me) for like 5 seconds and then it goes down to 40 mbps and starts fluctuating up and down for no apparent reason?

[nullable]

It's not my experience. But the differences between our systems might explain the disparity.

[Iceira]

Network do that then pc cant handle incoming data fast enoigh. ( work as intended )
if you cant recive data , then it will reduce payload to you, ( part of network protocol default )

[Supafly]

Steam downloads in compressed chunks, once a chunk is down it gets decompressed and installed. If the CPU and/or drive is at or near 100% the DL will slow and may even stop until the decompress and install is complete.

Open Task manager and see what CPU and the Drives usage % is at when this happens

[Satoru]

If you're patching, steam downloads the delta fiel and then begins re-creating the patched file. Steam doesn't download other thigns while this is happening because most people would be disk IO limited, which would just make the entire process overall slower as you run into disk IO contention

https://steamcommunity.com/sharedfiles/filedetails/?id=3150762353

As you can see I can easly get 400mbps from Germany to the east cost of the USA with a consistent 400mbps

Note this can also depend on the compression ratio of the game too. As in my screenshot the compression isn't too good on Destiny2. But if you have a highly compressible game, then you might download 1GB of data, but then need to extract 5-10GB onto disk

Also some games have very odd data structures. For example a 1GB patch for Payday2, requires that all 60+GB of data files be updated. So while the download doesn't take long, patching all 60GB of files does.

This can be further exacerbated by anti-virus programs constantly locking files to scan which slows down the download and patching progress as well.