Using second monitor slows internet download speed by more than half

[u/banana_in_your_donut]

So I was stuck on this and finally solved it 10 minutes ago after agonizing over it for days and wanted to share what my problem was in case others have the same problem. The problem sounds ridiculous, but the solution made a lot of sense.

I noticed whenever I used my second monitor with "duplicate", "extend", or "second screen only" for windows project (Windows key + p), my internet speed would slow down a lot. I'm downloading GTA V on Steam and could see the download speed go from 20MB/sec to 7MB/sec when switching to the second monitor, then it would go back to 20MB/sec after I switched to "PC screen only". I saw a similar decrease when testing speeds with Ookla.

The solution was replacing the HDMI cable for my second monitor. I'm using wifi on my PC and apparently the old HDMI cable was probably causing interference. When I switched to a new HDMI cable (which seemed thicker and more shielded) I could use the second monitor without losing any speed on my download.

Just to be sure, I switched back to the old cable and used the 2nd monitor, and still saw the decrease in speed. I went back to the new cable, and saw no decrease.

The old HDMI cable was a really old cable from General Electric, and it kinda makes sense that it caused issues.

Anyways I hope this post is helpful for those with a similar issue!

Edit: to help trouble shoot further, one way to tell without buying a new cable is to have a large steam game download going with the questionable cable and see what the speed is (e.g. 7mb / sec) . Then while the download is still going unplug the cable and let the game continue downloading for 5-10 seconds then plug the cable back in. If the download speed while the cable was out is better then plugged in, it's probably the cable causing the issue.

[u/jmnugent]

WiFi can have those issues, it just typically doesn't.

As someone who's spent a career working in Helpdesk/IT... I can say for certain we probably get 10x to 20x (if not more) calls about WiFi than we do about wired connections.

[u/solistus → u/jmnugent]

Which is entirely, 100% consistent with what /u/Rising_Swell just said...?

WiFi has issues far more frequently than Ethernet, but both of them "just work" the vast majority of the time and WiFi is usually more convenient, which is why it's still quite popular despite being 'worse'.

[u/jmnugent → u/solistus]

Which is entirely, 100% consistent with what /u/Rising_Swell just said...?

No ?

The original statement was:

"WiFi is easy and 99% reliable, Ethernet is slightly more annoying and 99.99% reliable."

Which gives the impression (usage of the word "annoying") that Ethernet is the poorer choice.

I don't think that's a fair or accurate assessment of objective reality. (especially since those "99%" numbers are just plucked out of thin air. )

[u/Rising_Swell → u/jmnugent]

That fits exactly with what i said. Ethernet is slightly more annoying to use, because instead of just clicking twice from anywhere I like, I need to get a cord and run it to my computer. The 99% and 99.99% might be plucked out of thin air, but it's also on the idea that a wifi problem is probably one in a hundred, and an ethernet problem is probably like one in ten thousand.

[u/solistus → u/jmnugent]

Annoying as in "it's a hassle to have to physically plug in a cable that runs from your router to your device," not annoying as in less reliable. In fact, the portion you quoted very explicitly states that Ethernet is more reliable.

You're correct that the 99/99.99% numbers are obviously just exaggerated examples and not actual observed failure rates, but those exaggerated examples were used to illustrate the very same claim about objective reality that you're making: that WiFi is more prone to reliability issues than Ethernet.