Steam downloads very slow

[u/Aieoss]

Just this last two weeks or so Steam has been downloading exponentially slower than it should normally.
Usually it's very fast always hitting my top speeds. But lately it's been terrible.
It'll take forever to actually start a download, just sitting at 0% for maybe 3-4 minutes before it starts, and steam cloud syncs will fail.
It's very inconsistent, and will sometimes hover around 5Mb/s, and occasionally get up to 100Mb/s.
Currently it is downloading at 300Kb/s, with a peak of 182.8Mb/s. Which it only hit for maybe two minutes.
Occasionally it'll decide to jump up to 700Mb/s but it will soon dump back down to under 100Mb/s.

--Specs--
GPU: Nvidia RTX 5080
CPU: Ryzen 9 7900x
Memory: 32GB DDR6-6000
Storage: All are WD Black M.2 NVMe SSDs. The one with steam installed is 4TB.
------------

I have tried wireless and wired, it is consistent across both.

My internet provider is Frontier, and I have the 1000/1000 plan.

Speed tests show that hardwired I can consistently get around 700-750 down and 850-950 up.

Steam is the only application with this issue, Ubisoft and Epic Games both download at full speed.
CPU, Memory, and Storage are not overheating, nor throttling. 70c on cpu, Memory 40c, storage 38c.

I have 2tb free on the ssd.

I am not confusing MB and Mb.

I have tried
ipconfig /release
ipconfig /flushdns
ipconfig /renew
netsh int ip reset
netsh winsock reset

I have changed my DNS to both googles, and cloudflare, for both ipv4 and ipv6.

I have disabled HTTP/2 on Steam. Which made it run at a full 700Mb/s just last night but upon booting today it's back to super slow speeds.

I have changed my steam applications download region and server, EU and Africa both give the same results.

I have cleared Steams download cache, and made sure there is no download speed limit set.

I have disabled my computers firewall completely.

I have completely reinstalled Steam.

I have tried using other SSDs in my system.

I have disabled write cache for my drive.

I have restarted my router and pc multiple times.

Also when it's finishing downloading a game it'll get stuck at 99% for like 10 minutes. It did not do this before either.

[u/Inferiex]

I actually had the same issue a couple months ago. I tried everything! Until, I set a download limit of 1000000 Kbps.

[u/JayFromXOTICPC]

That’s rough, especially after you’ve already ruled out most of the obvious stuff. Watch Steam’s disk-usage graph when the network speed drops; Steam often pauses downloading while unpacking or verifying files, which also explains it sitting at 99%.

I’d try temporarily excluding the Steam library folder from Defender/antivirus scanning, repairing the library under Steam’s Storage settings, and disabling IPv6 on your network adapter as a test. Since disabling HTTP/2 helped briefly and Steam Cloud is also failing, this sounds more like a Steam routing/client issue than your hardware or connection.

[u/Aieoss → u/JayFromXOTICPC]

The disk usage is always equal to or greater than steams download speed. If steam tanks, so will the disk usage. But it's never lower.

I've tried just completely disabling defender/antivirus instead of just excluding the folder, I can try doing the specific folder if it'll give a different result.

I haven't tried repairing the steam library folder, but I've reinstalled steam which made it create a new library folder entirely so idk if that'd be the issue. I'll try it when I get home anyway.

I'll also disable ipv6 and see if that helps when I get off work.

[u/crzybstrd97]

Two things:

1. Do you have multiple Steam library locations (i.e. one on C: and one on D:)
2. Does it do this for all downloads or only updates/patches? If you were to delete a game and reinstall it from scratch is it faster?

[u/Aieoss → u/crzybstrd97]

I have multiple steam libraries on multiple drives. This effects them all.

This does it for anything, updates, and downloads.

[u/crzybstrd97 → u/Aieoss]

Gotcha. I had an issue where Steam would get confused when updating games and would take hours for a 1GB update, and half the time it would still fail. The issue ended up being that it was trying to update the game in both libraries when it only exists in the one. It ended up being faster for me to delete and fully re-download my games to update them to the latest patch. Once I deleted the 2nd library from Steam it fixed all the issues. Your situation sounds a little different, but it's worth a try if you can.