Internet speed very low (Please help, urgent)

[PaPies]

I need some serious help with fixing the issue with my internet.
I've purchased a 1gbps internet but I am only getting an unstable 20-50mbps and 40-70mbps upload on my main computer, I gave it a try on my backup computer with lower specs like i5 and a cheaper motherboard and it works fine ish there, getting speeds of ~900mbps.
I need help fixing this issue on my main computer please!

 

[COLGeek]

You'll need to describe your network components so folks know what we are working with here. This includes: the make/model of your cable modem, router, type of Ethernet cabling, etc.

Also, on the main rig, is it using a wired or wireless connection? Are its network drivers up to date?

 

[PaPies]

You'll need to describe your network components so folks know what we are working with here. This includes: the make/model of your cable modem, router, type of Ethernet cabling, etc.

Also, on the main rig, is it using a wired or wireless connection? Are its network drivers up to date?

Okay so the main fibre cable that is coming to outside is connected to something called tetr@xs 2 outlet, that then connects to a modem called ZTE f660, which then is wired to the computer, I tested the speeds on my backup computer that has not been updated in ages and it works, but on my main one it doesn't reach anywhere those speeds!

 

[COLGeek]

Have you tried an alternate cable with the main PC? Also, have you tried an alternate port on your router (the ZTE f660)?

What is the make/model of your main PC's motherboard (to know what type of on-board Ethernet adapter is has, assuming that is what you are using)?

 

[PaPies]

Have you tried an alternate cable with the main PC? Also, have you tried an alternate port on your router (the ZTE f660)?

What is the make/model of your main PC's motherboard (to know what type of on-board Ethernet adapter is has, assuming that is what you are using)?

I have, I also tried the same port same cable on both computers, and one of them is ~900mbps(backup) and my main is unstable ~40mbps

Also I don't know anything on board, I am using Gigabyte z170x ultra gaming motherboard

 

[COLGeek]

Go here and get the most current network drivers directly from Intel:

https://downloadcenter.intel.com/download/25016/Intel-Network-Adapter-Driver-for-Windows-10?product=36773

Install and re-test your performance.

 

[PaPies]

Go here and get the most current network drivers directly from Intel:

https://downloadcenter.intel.com/download/25016/Intel-Network-Adapter-Driver-for-Windows-10?product=36773

Install and re-test your performance.

I downloaded it from the gigabyte website, version seems to be the same but 5 times larger in file size, if that doesn't work I'll try intel itself.

 

[PaPies]

Go here and get the most current network drivers directly from Intel:

https://downloadcenter.intel.com/download/25016/Intel-Network-Adapter-Driver-for-Windows-10?product=36773

Install and re-test your performance.

No change, I installed the gigabyte version of intel, then directly from intel, restarted twice and no difference sadly!

(edit 2)OKAY SO I REMOVED THE MAC ADDRESS BY CLICKING "DEFAULT" as this new driver actually tells you troubleshoots right there and out of nowhere it works now..

 

[PaPies]

Go here and get the most current network drivers directly from Intel:

https://downloadcenter.intel.com/download/25016/Intel-Network-Adapter-Driver-for-Windows-10?product=36773

Install and re-test your performance.

Thank you very much for your time and answers it really means a lot to me, it motivated me to try so many different things that I wasn't comfortable to try on the computer.

I will mark one of your answers as a solution even though that wasn't the thing it fixed it, but it kinda did thanks to the troubleshooting steps it had on each tab!