[SOLVED] Network speed slowing to a crawl 10-20 minutes after startup/adapter reset - "default gateway not available"

[GrandpaDave]

I'm completely at my wit's end for this one. Since December, my PC's download and upload speeds have been so much slower than my laptop and my phone. On startup, it gets the same speeds as the other devices, but slows to 1-2 mb/s (yes, it slows to that amount).

Obviously, it's my PC and/or it's network adapter which is at fault - an ASUS USB-AC51 wireless adapter. Sometimes if I deactivate my network adapter, it will reset to the speeds I previously had for varying degrees of time, and sometimes it won't. Sometimes my PC's connection goes down entirely after a while, after which I troubleshoot my network by right-clicking the lower right icon, after which it will say "resetting wi-fi" and give me a default gateway not available message (stolen from the internet, but it's the same one), which seems to fix it every time. It's like dark magic for when it works and when it doesn't.

Things I have done (that didn't fix it):

• Flushed my DNS multiple times
• Switched to Google's DNS and back
• Updated every driver I could find
• Done a clean installation of Windows
• Turned off all power saving options related to network
• Turned of AV and firewall

I have not been able to find a fix anywhere on the internet, which is rare for issues like this, and I'm completely out ideas. The router is in my roomate's room, so switching to ethernet is sadly not a possibility either. If anyone can help me fix this, I would be extremely grateful. Thank you all in advance

Specs: Windows 10 Home v. 1903
Intel i7-6700K @ 4.0 GHz
EVGA GTX 1070
8 GBs of ram
(Let me know if anything crucial is missing, I'm still not 100% adept at computers)

 

[Ralston18]

Before turning on the PC feel the USB wireless adapter.

Then boot up and work/game as normal. While doing so occasionally carefully feel the USB adapter.

Determine if the USB adapter getting warm and even hot?

If so, the USB adapter is likely nearing design EOL (End of Life). Its' ability to function will suffer accordingly.

You may be able to use a USB extension cable to move the USB adapter up and away from its' host computer.

Two benefits: cooler air and possibly more open transmission/reception. You may recover full use to some degree or, depending on how far gone the adapter is, it may continue to degrade.