Lost 2/3 of my internet bandwith, is it my motherboard?

[phipps.steven]

Lost 2/3 of my bandwidth. I pay for 200Mb internet service. On every hardwired PC in the house, internet speedtests report back around 225Mb download speed. My hardwired gaming PC used to as well but all of a sudden it is only showing speeds of around 75Mb download. I have done the following trouble shooting with no success fixing the issue. Used an ethernet cable from one of the PC's that tested at 225. Connect the PC to a modem port that tested at 225 for a different pc. Reinstalled Win10 64 with the remove all files option. Downloaded all most recent drivers from asus for my H170 pro gaming motherboard. Ran internet speedtests from edge & chrome and still I get around 75 instead of 225. I'm starting to lean towards a motherboard failure. Is there anything else I can test before I replace the motherboard?

 

[kanewolf]

Boot safe mode with networking and test. That will eliminate most OS type things.

 

[phipps.steven]

Tried the safe mode suggestion and still getting speedtests in the 70's

 

[kanewolf]

What speed does the interface say it is operating? My guess is 100Mbit.

 

[drea.drechsler]

…. I'm starting to lean towards a motherboard failure. Is there anything else I can test before I replace the motherboard?

Plenty of things to do:

Check ethernet negotiation setting: force-set it to 1Gb full duplex.

Rather than replace the whole motherboard just get a decent gigabit ethernet NIC like:

https://www.newegg.com/Product/Product.aspx?Item=9SIA4A05HY4138&cm_re=gigabit_nic-_-33-106-033-_-Product

Both a lot cheaper and easier to remedy. This of course assumes your motherboard ethernet really is failing and isn't just misconfigured.