How to troubleshoot a slow internet connection

Are you paying for a crappy internet experience at home? Do you know whether it’s your devices, the WiFi, the connection, or something else? Did you pay for an upgrade in speed and see absolutely no change? Did you get sold a repeater to increase the WiFi and noticed not a thing change even though you have better signal?

TL;DR some steps to try to diagnose where the issue is. Lot of text. Not selling anything. Lot of text.

You’re not alone. Most people don’t know how to diagnose what is actually the slowdown and there are not a whole lot of great tools out there to walk you through doing this. Here are some things you need to know and how as an IT pro, I’ve been diagnosing network slowdowns for a couple of decades.

The chain / weakest link / strong as

The slowest part of your network is the fastest you’ll ever go. If your WiFi is slow, that’s the fastest you’ll go on WiFi. If your internet is slow, that’s the fastest you’ll go on the internet, even if you get better WiFi. If you’ve got a computer with a 100mbit ethernet card or dongle and a gigabit connection, you’ll get 100mbit. If you’re using a USB ethernet dongle, well, the specs on USB2 say 480mbit but I’ve seen effective performance well below 60.

Kitties unlock the internet from pixabay

The slowest part of your internet is as fast as your internet is.

Understand what uses (internet) bandwidth

You’ve got this awesome 200mbit connection and you’re having issues and blaming your kids watching Netflix is why you can’t browse Facebook or complete a video chat. Shut that nonsense down.

Netflix: 1-15mbit
Zoom : 3.8mbit (it can go slightly higher, but that’s about the max with HD video)
Gaming: 1-22.5mbit
That IOT device: nothing.. I can’t stress enough how little bandwidth your smart bulb, lock, etc use.
Connected camera streaming to the cloud: 0.8mbit-1.6 per camera maxing out at 2mbit during recording events (depends on camera, but that’s about average)

Seriously, none of that is making a dent in a 200mbit plan. You have 200mbit, using this for browsing, Netflix, etc, you are not coming anywhere near what you’re paying for. In 2022 most people don’t even max out a 50mbit connection. Companies selling two gig connections for “all your household gadgets” kill me.

But you’re having problems, I get that.

Understand that internet bandwidth is not WiFi bandwidth

You can have a fabulous internet connection that is abysmal on WiFi. The general symptoms of this are that it works pretty good when you’re near the equipment but it’s garbage the further you get away. Here’s where repeaters and mesh units get mentioned to boost your signal. Your signal generally isn’t needing boosted and most of these products will increase the signal strength you see but not speed anything up.

Why is that?

A repeater, WiFi Range extender, etc. takes what it’s hearing and re-broadcasts that on a different channel and name. Did you put that repeater where you were having bad WiFi? Well, that repeater is having bad WiFi as well and is repeating that, but much louder. These things only work decently when they can hear a good signal. You put that repeater in a bad signal area and it’s not going to do anything except broadcast a very strong signal backed by a very weak connection from the repeater to the WiFi it’s repeating.

You can have a gigabit internet connection attached to a 3+ Gbit multi-channel capable WIFi router that is complete garbage but has a strong signal and barely get Facebook to load.

Why is that?

WiFi is a two way street. Your device broadcasting requests, and the WiFi router broadcasting data. It’s line of sight. If you can see the router, chances are you’ve got a great signal. Due to not every house and building having absolutely no walls we start having issues. Your WiFi router, plugged into an outlet and broadcasting at near the max allowed by the FCC can probably be heard down the street if you wanted to check it. Capable of pulling all the power of the cosmos through its little power plug, broadcasting is probably not an issue for it. It screams the internet wirelessly in all directions.

Your phone or tablet, designed to sip a teacup worth of electrici-tea throughout the entire day, whispers a polite request in another room behind a wall filled with wires, wood, and insulation that mess WiFi signals up.

WiFi router requests your device re-send the request for data

If looking at your WiFi router you’re having great signal but your cement bunker basement isn’t, you need to figure out line-of-sight placement.

First step: rule out ISP

I start from the source back generally. In this case the router that my ISP provides, whatever the thing is hanging off the cable, etc. Top of the chain. First test for me generally is to take a device I know can achieve decent wired speeds and plug it into the ethernet jack using a CAT5 or better cable. These are all standard cables now, but if you’re pulling cheapo cables from years ago make sure it’s capable.

Install a speedtest app. You might want to just go to speedtest.com, or any of them, but if you have fairly low download speeds I’d hit an app version as I have had absurdly weird and inconsistent results in the past caused by browser issues. So if it’s slow, grab and app to verify it’s slow.

If plugged into the back of the router things are fast but your WiFi sucks, move on. If it’s slow here ask your neighbor if you can test their incredibly good network to verify your laptop is capable of testing at high speeds. Just because you’ve got a good laptop doesn’t mean they put in a good network card. I mean, these days it generally does but just saying.

Understand your WiFi / it’s probably the issue

While nothing you’re using or your kid is using is probably messing with the internet connection, WiFi can be affected by multiple factors. Use, unfortunately being a big one. Distance, walls, line of sight issues.

Does your internet become unusable when the kid is on Netflix? I don’t doubt you, it’s probably not your ISP (or at least their upstream connection,) as we probably already ruled out. It’s probably your WiFi.

There are a lot of WiFi access points and routers out there. Many of them come from your ISP. I can’t get into every one, this is a problem. Some are garbage.

OK, so here’s some troubleshooting ideas for WiFi, after having ruled out that your ISP is bad.

Go into the room and stand near the WiFi. Speedtest. Is it good? great.
Have a friend, or use a different device, do the same test in the same approximate location.
Move to different areas, speedtest, speedtest, speedtest.

As you walk away you should expect speeds to drop a bit, but going from 300mbit to 270mbit isn’t a concern. It’s when you go from 300mbit to 12mbit that we’re into unusable levels.

When you’re at the extreme ranges / usually where your kid’s netflix tablet is being used, move 5 feet to the right, test, 10 feet to the left, test, etc. See if there’s any difference because you might have something in between your device and where ideally you want to receive internet. Fireplaces are a common WiFi killer.

You’re probably here wondering why we’re doing a test on the kid’s device area – that’s because a lot of the WiFi routers out there are complete garbage and when Kid has an issue requesting Netflix data the WiFi router will pause every other connection for just a second until this one little data block is retransmitted. Like, wait, wait, just hold on a second everyone else who can hear me fine, this little bit of Netflix needs to get up there… oh you misheard me? One more sec guys, really…

This is not a problem we should have in 2022, but it is. Cheapest bidder, crappy firmware updates, and a lack of real-world testing often mean things that should have been ironed out in 2008 pop right back into routers.

Understand the internet doesn’t just send you data

Watching Netflix you might feel like you’re just receiving a constant stream of data. That’s not the case. Your client (tablet, tv, etc) requests a block of data. This is sent as a packet request to the WiFi access point. The WiFi access point takes this and passes it to your internet gateway. The Gateway sends it upstream to probably 8-12 different locations before it’s received by the Netflix servers as a request for a block of data which is then sent in the opposite direction.

I don’t know the exact numbers on this, but it’s safe to assume you send several thousand/hundred thousands of requests for data for a short show.

If your WiFi doesn’t hear it (there are confirmations,) or the Gateway doesn’t get it, or anything along the chain breaks, well… there’s a pause and then a retry. Get enough of these and you start noticing.

When you’ve got a great download and crappy upload speed, chances are pretty high that your requests for data might be having a problem getting out.

What can cause slowdowns, in order of what I’ve seen

Bad WiFi Router / usually the receiver failed.
Bad WiFi Router / backplane (port) bad – saw three of these in the past two years
WiFi related / cheap ethernet cable that worked, wasn’t moved, and then became bad – this has happened way too many times. Grab a different cable.
WiFi line of site / something changed, now there’s something in the way
ISP / in 30+ years of doing this I’ve seen the ISP be the culprit about three times on anything ongoing. Most investigations I get called into it’s above this line.
Device issues / just because your phone works on John’s WIFI doesn’t mean it’s going to work on yours. All WiFi access points use different channels on the 5ghz and 2.4ghz spectrums. You might be on channel 36 on John’s and 149 on yours and that slight difference can make your experience suck.

Wrap up

Test with many devices in many locations. Don’t blame the ISP first. Understand that when Jake got a Comcast/XFinity tech to come out and “fix it,” chances are the tech moved Jake’s power brick that was sitting on top of the gateway, removed the tangle of extension cables, and put the gateway where it was supposed to be. Unless you know what the actual fix was, even if they swapped the equipment in front of Jake, it could be the moving of equipment was the issue.

You can rule that out by testing near and then testing far.

PS … don’t get me wrong, your ISP could indeed be nothing but garbage people selling a garbage service, your area might be suffering years-long oversubscription and under-fixing. You’ll see testimonials to that anywhere you go – probably comments here will reflect that as well. I had an issue with Comcast/XFinity for years that was not in my house (it was a cable they’d run that filled with water and when it got hot I lost speed and internet) – but most of the issues I hear are WiFi / user side.

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Paul E King

Paul King started with GoodAndEVO in 2011, which merged with Pocketables, and as of 2018 he's evidently the owner. He lives in Nashville, works at a film production company, is married with two kids. Facebook | Twitter | Donate | More posts by Paul | Subscribe to Paul's posts