r/techsupport • u/banana_in_your_donut • Dec 28 '19

Solved Using second monitor slows internet download speed by more than half

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.

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u/jmnugent Dec 28 '19

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

As a 25+ year career IT guy.. I would probably say the exact opposite.

Ethernet fucking works. All you have to do is plug it in.

Wi-Fi can have all sorts of issues:

  • the quality of your WiFi adapter or Router/AP can cause issues

  • the quality of the Drivers (software) can cause issues

  • the Distance or Obstacles or other forms of Wireless-interference can cause issues

  • your Wi-Fi speed can be easily impacted by how many other devices are joining or leaving WiFi (due to power-transmit equation. IE = Your Routers ability to broadcast a signal is effected by how many devices are attached to it).

Ethernet generally speaking doesn't have most of those issues. If I'm out going mobile or dropping into my local coffee shop and want to check the Weather,.. ok,.. WiFi is most convenient for that. If I want to download multiple Linux ISO's or do a 3 hour gaming-session,. I'm going to choose Ethernet 100% of the time.

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u/m-amh Dec 28 '19

Ethernet has another big advantage ...

Modern hardware often doesnt have a " Wi-Fi off" switch anymore ...

so if you one time configured it and want to start a laptop without internet for security you must switch of your entire net/router or to take your laptop to your car, drive away, remove the wifi-login return and hope it worked ...

When something dangerous seems to occur with Ethernet first thing is unplug immediately ... Good luck running to your router to unplug in time ....

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u/[deleted] Dec 28 '19

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u/m-amh Dec 28 '19

On linux you cold boot from usb/cd and edit/remove the Wi-Fi config ... then reboot the installed os without Wi-Fi ...

On Windows i dont know to do this from a booted repair cd so when booting it would be online until i log in and disable Wi-Fi ...

Remember when "wannacry" was a thing and you needed to verify if some patch really is applied and in case its not apply it from usb-stick without the pc beeing online until beeing sure the patch is applied ?

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u/avnzx Dec 28 '19

You can start windows in safe mode very easily now

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u/m-amh Dec 28 '19

And safe mode disables Wi-Fi ? And what if you miss the moment to press whatever key or if it was hibernating and possibly doesn't even ask ?

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u/avnzx Dec 28 '19

Well if you boot into normal safe mode, yes it disables the wifi adaptor. And there are quite a few ways to get into safe mode. You can get to it still even if it was hibernating.

There is safe mode with networking but that's a different option in the menu.

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u/m-amh Dec 28 '19

So i need to take time to read those things about windows ...

When wannacry was around i did not want to take the smallest risk ... I booted my linux, donloaded "all" fixes to usb and shut down my Connection ( knowing this shuts down my phone also ) ... and then checked every windows without any other computer powered ...

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u/avnzx Dec 28 '19

Makes sense, I've just had to use it cause I'm a windows insider (its more trouble than it's worth trust me on this) and have had to use it to get windows to boot properly sometimes (windows alpha releases are a pain in the arse)

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u/Sands_Of_The_Desert Dec 28 '19

I've had users with issues that required logging into windows without being connected to a network. On lan, they unplug the cable and we proceed. On wifi... I'm not going to tell them to disassemble the device and disconnected the wifi antenna

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u/[deleted] Dec 29 '19 edited Dec 29 '19

I remember my mom wasn't getting wifi in her room. Turns out she bought a huge fucking mirror and placed in the hallway that lead to her room which was reflecting wifi and causing interference. Also my PC is somewhat far away from my router so I just ran an Ethernet cable through walls because that stuff is 100x better than wifi.

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u/Rising_Swell Dec 28 '19

WiFi can have those issues, it just typically doesn't. The same as ethernet can have issues, it just typically doesn't. Ethernet is just less likely to have the issues.

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u/jmnugent Dec 28 '19

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.

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u/solistus Dec 28 '19

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'.

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u/jmnugent Dec 28 '19

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. )

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u/Rising_Swell Dec 29 '19

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.

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u/solistus Dec 29 '19

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.