The wired internet speed on my desktop specifically has suddenly slowed from 100+ Mbps to 30~.

[Coheed_]

A week ago I noticed a drop in internet speeds on my desktop.

I thought it was a problem with Time Warner, so I got a technician to check it out. When he came, it became apparent that the issue was with my computer specifically as the using the same ethernet cord yielded 100+ Mbps on my laptop but around 30 Mbps on my desktop. He offered no solution other than messing with my firewall. I didn't think this was the issue, but I disabled my firewall to check with no avail. I've done everything else I could think of including:

flushing DNS
changing to google DNS
malwarebytes scan
antivirus scan
updating bios/ethernet drivers
restarting the modem and my computer
installing a network card

The fact that this problem arose seemingly randomly has me baffled. My build is only a year old and pretty decent so it shouldn't be a hardware problem (confirmed by the network card?). Any suggestions would be greatly appreciated.

 

[Ralston18]

Any new software installs? Any known updates (software or drivers)?

Double check your ethernet adapter's configuration. Make sure that it is matched to the router. No "automatic" settings. Or if already specifically set try auto.

Even though the ethernet cable worked on the laptop did you try another known working ethernet cable on the computer? Does not take much to cause a cable to have intermittent behavior. The laptop's port may have been just a bit tighter and the problem failed to manifiest itself.

Are you using wall ports - i.e., your residence has ethernet wall jacks. If so there could be a problem in the jack, the connections on both ends, or the cabling in between.

Check the computer's logs via Event Viewer. Look for error codes and messages corresponding to the times that the speed dropped. Either just before or at the time of the drop.

Even though the build is only a year old stay open-minded there. Hardware is being build nowadays as cheaply as possible sans any meaningful QA. The network adapter could be failing.

 

[Coheed_]

Any new software installs? Any known updates (software or drivers)?

Double check your ethernet adapter's configuration. Make sure that it is matched to the router. No "automatic" settings. Or if already specifically set try auto.

Even though the ethernet cable worked on the laptop did you try another known working ethernet cable on the computer? Does not take much to cause a cable to have intermittent behavior. The laptop's port may have been just a bit tighter and the problem failed to manifiest itself.

Are you using wall ports - i.e., your residence has ethernet wall jacks. If so there could be a problem in the jack, the connections on both ends, or the cabling in between.

Check the computer's logs via Event Viewer. Look for error codes and messages corresponding to the times that the speed dropped. Either just before or at the time of the drop.

Even though the build is only a year old stay open-minded there. Hardware is being build nowadays as cheaply as possible sans any meaningful QA. The network adapter could be failing.

Trying a new cord was indeed the solution. I didn't try this because the cord goes from downstairs to upstairs and has to be long so I didn't think I had another one but it turns out I did. I thought the laptop test ruled out a cord issue as well but I suppose this was a bit ignorant of me. Thanks for the help.

 

[Ralston18]

Excellent - glad it worked.

Please do not consider it as "ignorant". Intermittent problems are always tricky and it is not at all uncommon to have two cables "misbehave".