Degrading ethernet speeds

[JohnP]

I have spent hours on the phone with customer service for my motherboard and they blame it on hardware. I just purchased a different motherboard to confirm it is not hardware. I cannot figure out why the Intel i225-V 2.5GB ethernet ports do not work correctly. 

Basically, when I run a speed test when something like a YouTube video is playing, the speed will begin to degrade halfway through the test. If I close the video I get my full 1200mbps speed. My ISP is Xfinity. Yes I have made sure my drivers are to do date and even used Intel's tool to scan and be sure. This is so frustrating, I will appreciate any help. I adjusted some settings in the "Advanced" tab as well but those made no difference so I reverted them.  

My old motherboard which had a 5GB Marvell ethernet port worked perfectly fine. No degrading issues. All of the Z590 motherboards come with Intel i225-V. I have to figure this out somehow, if someone would be so kind. I can post a video to YouTube if needed. 

Motherboards I have tried that both have the same issue: 

ASUS Z590-E Gaming WIFI
MSI MPG Z590 Gaming Carbon WiFi Gaming

[Caguicla_Intel]

Hello JohnP,

Thank you for posting in Intel Ethernet Communities. 

We are sorry to hear that you are experiencing issues with your Intel® Ethernet Controller I225-V. Rest assured that we will do our best to help in resolving the issue.

Before we further check your query, can you confirm if you already followed the steps from link below for Network Issues with Intel® Ethernet Controller I225-V?

https://www.intel.com/content/www/us/en/support/articles/000057261/network-and-i-o/ethernet-products.html

Looking forward to your reply.

We will follow up after 3 business days in case we don't hear from you.

Best regards,

Crisselle C.

Intel® Customer Support

[Caguicla_Intel]

Hello JohnP,

Good day!

We'd like to check if you are able to read our initial response on this query. If yes, kindly provide the information requested for us to proceed checking on this.

Awaiting to hear from you.

Should there be no reply, we will follow up after 3 business days.

Best regards,

Crisselle C.

Intel® Customer Support

[Caguicla_Intel]

Hello JohnP,

I hope this message finds you well!

Please be informed that we will now close this request since we haven't received any response from our previous follow ups. Just feel free to post a new question if you may have any other inquiry in the future as this thread will no longer be monitored.

Best regards,

Crisselle C.

Intel® Customer Support