Why do my WIFI speeds often drop down to 1 mbps from 100 mbps?

February 6, 2015 10:40 AM

I use Grande Communications internet in Austin Texas, (110mbps up 10 mbps down) my Wi-fi speed able to attain on my laptop in the same room as the modem is about 100mbps. Often, from the same location, the highest speed I can attain (speedtest.net) is like 2mbps. I tested on my laptop and phone. I reset the modem to factory settings, I changed the channel of wi-fi. No one else is using the same channel as I am, and it usually only drops to slow in the evening, and by morning it's better. (I am using a top of the line Arris Surfboard SBG6782-AC which cost about $200)
posted by crawltopslow to Computers & Internet (9 answers total)

There's two legs of your connection to test here: Your home router to Grande, and the router to your laptop. Are you able to speedtest through a wired connection in your laptop? This will let you test the cable connection itself, taking WiFi out of the picture for a moment. Do you ever actually get the 110M you are paying for? Test at different times of the day if possible.

Depending on the technology between your building and the cable company, your cable bandwidth is likely shared with your neighbors, it's normal to see some significant sagging in available bandwidth. Getting 2M out of a 110M account, though, well, that's either an overburdened neighborhood connection (not unheard of) or some bad connectivity.

For 2.4GHz wifi in the US, you should be using channel 1 or 6 or 11. Using any channel in between loses more to interference from adjacent main channels. If you're using 5GHz, you should be able to locate a group of 5 or so empty channels and pick a channel in the middle.

To test WiFi, try transferring a large file from your phone to your laptop, or vice versa, over WiFi. Also, expect lower speeds for your phone vs. your laptop over wifi because your phone is a lower power device overall.
posted by Sunburnt at 11:23 AM on February 6, 2015

It isn't necessarily your wireless. The wired infrastructure that goes out from your wireless router to the internet is shared by other people in your building (if an apartment) and in your neighborhood. Evening is the busiest time of internet use, so it could be congestion on the local wired portion.

Can you connect with an ethernet cable one evening and see if that makes a difference? It could help rule out wireless problems.
posted by procrastination at 11:24 AM on February 6, 2015

And your WiFi can be negatively impacted by someone using a microwave... there are various potential sources of interference between your laptop and the router.
posted by straw at 11:46 AM on February 6, 2015

speedtest.net is measuring your bandwidth to their server. Barring any weird wifi issues, as others have outlined, it's more than likely your service provider. You can confirm this by unplugging your wireless router, plugging your computer directly into the cable modem, and trying the test again.

Long story short: It's slow in the evenings because your neighbors come home from work and your provider's local endpoint is saturated.
posted by mikeh at 12:07 PM on February 6, 2015

Dollars to donuts that this is your ISP, or their last-mile provider. Do you know if the infrastructure (cable, or fiber probably for the speed) is owned by Grande, or if they're a reseller of someone else? If they're a reseller, it might be worth inquiring if Grande has their own speed test servers on their own infrastructure? If the speeds to that are good, but not to speedtest.net, then the ISP's problem is with their upstream provider(s).

If the speed even to their own speed test system is low, then the problem is with the infrastructure.

The cable/fiber might be a 100mbit interface, but if the other end of that is 192+ devices, all sharing a 1000MB interface to the next uplink, there's going to be contention. Similarly, your ISP probably has a few upstream providers, but if they have 1 10GB connection, and 3 1GB connections and they've got people trying to pull 40GB of data... well, you can't.

Note, I'm assuming that when you say your wifi speed, I'm assuming that you're testing from one device on your wifi to another on your lan (or wifi), as opposed to just saying what the interface reports as it's max speed. And that you are testing this at the same time that the internet is slow. If not, you really need to test that. Install something like: Speedtest Mini on a home server, and test your laptop/phone against your local IP. If that's maxing around 2mbit, then it's definitely your wifi.
posted by nobeagle at 12:11 PM on February 6, 2015

Response by poster: I test the wired connection often, it is always at or very near my advertised rate of 110 mbps rate. I test the wi-fi at night and it's 2mbps, I test the wired at night, and it's still over 90 mbps.
posted by crawltopslow at 1:50 PM on February 6, 2015

integrated modem/wireless ap combos are unusual when they don't suck. even a cheapo router will be a huge improvement. even something like this will likely be a mindblowing improvement, and never screw up like this again.

so, so many problems i've troubleshooted or just mucked around with on those combo modems. ugh.
posted by emptythought at 3:30 PM on February 6, 2015

So if your wired connection is always good, and it's the wi-fi that goes bad, I think you are getting interference. WiFi operates in unlicensed spectrum which means anyone can use it. Like someone said, microwave ovens can cause interference. Your neighbor's wifi can cause interference. There are cheap/free tools that will use the wifi receiver in your laptop/smartphone/tablet to show you the wifi networks around you including their power levels. This is an example from the Google Play store.

You could try just switching your wifi to another channel and see if that helps. Or, perhaps move the modem around. Or, if your computer does both 2.4 and 5GHz wifi, try switching to the other band.
posted by elmay at 5:35 AM on February 7, 2015

Electromagnetic interference (EMI) is a likely culprit, and its source is sometimes surprising. I recently had trouble with my wifi, but only intermittently, and only in one room. It turned out to be the electric motor in my new treadmill desk interfering with the signal. I got a cheap USB wifi adapter and moved it a little ways away, and it helped a lot.

Anything with an electric motor (e.g., fridge) or a magnetron (e.g., a microwave) can easily cause EMI.
posted by Hot Pastrami! at 10:10 AM on February 8, 2015