[SOLVED] download speed drops exponentially after a few seconds

[zear12]

hello, i just upgraded my internet from 100mbps to up to 400mbps through spectrum cable internet.

my specs:

i9-9900k
MSI GEFORCE RTX 2080TI GAMING X TRIO
32GB RAM
ASUS ROG MAXIMUS XI HERO (WIFI)
RM850x

Windows specs:

Edition: Windows 10 Pro
Version: 21H1
Installed on: ‎3/‎1/‎2021
OS build: 19043.1288
Experience: Windows Feature Experience Pack 120.2212.3920.0

Router: Netgear Nighthawk r8 x6000

When I run speedtest it counts usually near or above 400mbps download, with a 10-20 mbps upload.

I've spent countless hours looking and attempting fixes or trying to find the problem here. When updating a game before upgrading my internet it would be at a stable 10-11 mbs.
Now with the upgraded internet the download speed when updating a game is 20-22mbs for the first 10 seconds or so then it drops to less than 800kbs and will not pick back up unless I unplug my ethernet cable and connect to my internet wirelessly. Either or, same ending result. I've tried going straight from my modem to my PC with no router in between, same result. I've called my ISP and they said everything looks fine on their end. I've changed my ethernet settings so there is more priority towards it and still same result. I tried different ethernet cables also. I have multiple coax cables running under/throughout my house so I am not sure if the problem lies in old cables or switching them out as I would not be able to test this theory with a wired connection because I can not move my pc that far. Please reply with help and possible fixes, if I am missing any information I can provide asap.

 

[bill001g]

Look in the log in the modem and see if there are any messages that might correspond. I would also look at the signal levels. You can find the recommended values with a search, the exact values vary a bit with different types of docsis so I didn't just want to cut and paste that document here.

If the values are good in particular if the upload levels are fine then it is not likely your coax cables.

The difference between speedtest and game downloads is mostly that the speedtest runs in the browser and the clients run their own file transfers. You could try a simple browser download of say win10 from microsoft. You can watch the rates in the network tab of the resource monitor.

Asus bundles some crap "gamer" network software with many motherboards. Try to uninstall that it tends to cause strange issues. The software has almost no value. It can not affect traffic outside your machine and if you have overload issues with traffic inside your machine you are doing something very stupid like running torrents when you try to play a game.

 

[zear12]

I do not think it is possible to check spectrum modem logs.

I did the browser test to download a 1gb file and it did download 15mbs average the whole time.

 

[bill001g]

Try putting 192.168.100.1 in the browser and see what happens. This tends to be the IP most modems use. Since there really is nothing you can change in a modem you do not even need a user/password.

I assume you mean 15MBYTE which is still slower than what you pay for. You should see downrates closer to 50MBYTE. The number you get is acting like you have a port running at 100mbps rather than 1gbps. There should be some kind of status screen that shows you the speeds of the ports. Look at both the wan and lan ports and see what speed they are running at. Many routers also have lights on the ports and you can tell the speed with those. You are going to have to check the manual since the actual color is not consistent between routers.

If all the ports are gigabit then it is not as likely that it is a bad cable.

It then has to be some kind of software limiting the transfer speeds. Find it is always a challenge