Q: Why is my internet speed so slow?

A: When purchasing a broadband connection from your DSL, cable, satellite, or another provider, you are sold a package with an estimated top speed–such as 20Mbs download. But it is exceptionally rare to get this speed. We receive complaints from clients almost every day about this, asking how we can fix the slow speed problem.

Unfortunately, the real problem is the broadband provider isn't forthright about what that 20Mbs means, which sets up unrealistic expectations for the buyer. So let's see if I can clear some of the fog.

What does internet speed mean?

When purchasing a broadband package of say, 20Mbs, this means that under ideal conditions (we don't live in an ideal world), the total amount of data that can be pushed from the broadband provider's central office to your gateway (often referred to as the DSL or Cable modem or router) is 20Mbs. However, up to 20% of that is handshaking and other activity that does not include your actual data. So even under the best of conditions, you will likely only receive 80-85% of the rated speed. In this example, 20% of 20Mbs is 4, so 16Mbs will be realized.

Many providers do not even mention what to expect for upload speeds, and most residential users make little use of upload except for sending an email. However, for a business that hosts an internet server, or needs to send graphics or video over the internet, upload speed is vitally important and should be negotiated at the time of purchasing your plan.

How to test internet speed

To get the most accurate measurement of internet speed:

  1. Connect a computer directly to your broadband gateway device via ethernet.
  2. Disconnect all other Ethernet and Wi-Fi devices from the gateway.
  3. Open a browser to the appropriate speed test site (below).
  4. Run the test.
  5. If your speeds are within around 20% of what you are paying for, all is good. If they are slower than this...
  6. Power off both the gateway and the computer, wait a minute, and then power on the gateway and computer.
  7. Wait until both are fully up and running.
  8. Repeat steps 1-5.
  9. If the speed is still not within 20% of expected, time to contact your broadband provider and hand off troubleshooting to them.

If the measured speed when directly connected is good, but there are speed problems with WiFi:

  1. Disconnect all ethernet and Wi-Fi devices from the network (usually easiest to just power them off).
  2. Connect one computer to the network, via Wi-Fi, and place the computer right next to the Wi-Fi base station.
  3. Open a browser to an appropriate speed test (bel0w) and measure the speed.
  4. If speed is within 25% of expected, all is good.
  5. If the speed is not within 25% of expected, power off the gateway and Wi-Fi base station, wait a minute, and then power on.
  6. Repeat steps 1-3.
  7. If the speed is still not within 25% of expected, time to contact an IT consultant to determine what is undermining your speed.

To measure your internet speed, your broadband provider has a website. Start here:

What can degrade internet speed?

  • Old network equipment. Older equipment (including your DSL or Cable gateway, router, switches, wifi base stations) may not have been designed for the speed provided by your broadband provider. Also, as equipment ages, its stability and performance degrade. Consider 3 years to be a useful lifespan for network equipment.
  • Old ethernet cable. Ethernet cable degrades over time, reducing speeds. Older ethernet cable may only be capable of transmitting 10Mbs, which then becomes the bottleneck to all traffic. Howe the cable is installed makes a big difference. Many people have installed ethernet using rounded staples. That pretty much guarantees substandard transmission as the staples put a crimp in the cable, effectively putting a road bump every foot or two.
  • Long ethernet cable. Under ideal conditions (remember, we don't live there), ethernet can be 100m long. However, as soon as there is a sharp bend in the cable (around 1" or less), staples, etc, the maximum length dramatically decreases.
  • Running ethernet cable along with power cables. Using velcro ties to wrap all computer cables together into one, nice, neat bundle sure looks great. But the ethernet signal is slowed as the electromagnetic field around the power cable overwhelms it.
  • Multiple devices. Keep in mind that network bandwidth is a time-sharing system. If there is only one device on the network, it gets all of the available bandwidth. Put 10 active devices on the network, each gets around 1/10 the available bandwidth.
  • Streaming video (Netflix, Amazon Prime, Hulu, etc.) take up far more bandwidth than any other function. If your bandwidth is under 10Mbs, video streaming may be taking the majority.

WiFi presents its own issues:

  • The very best wifi is able to provide 1,300Mbs. Models that are currently on the store shelves but using slightly older technology will max out at 300Mbs.
  • Wi-Fi is time-sharing. The more devices on the Wi-Fi, the slower each will be.
  • Distance. Wi-Fi uses electromagnetic energy. Electromagnetic energy decreases significantly as sender and receiver move apart. Mathematically, the energy decreases to the inverse square of the distance. So, if the sender and receiver move 3x further apart, the energy between them decrease to 1/3x3 or 1/9 the original!
  • Energy-absorbing objects will greedily take the Wi-Fi signal. Metal (TV, oven, refrigerator, mesh inside walls, metal desk, concrete, bricks, etc. will all dramatically decrease the Wi-Fi energy reaching your device or the base station.
  • Conflicting Wi-Fi channels. There are a limited number of Wi-Fi channels. If the channel your network uses is within 1 channel of another Wi-Fi within range, yours and theirs will conflict. This is much like trying to hear and understand two conversations at the same time. There are free apps to show all available Wi-Fi networks and channels in use.

Other factors:

  • Everything in the computer world operates on time-sharing. If you have two or more active processes accessing the network or internet, each slows down the performance of the other. For example, if I'm watching a streaming movie, while at the same time downloading an application update, the movie may well end up stuttering and pausing as it gasps for bandwidth.
  • Just because your internet provider gives you 20Mbs (or whatever speed) from its central office to your gateway, doesn't mean the service or website you connect to have anywhere near that bandwidth. If a website is connected to the internet with a 10Mbs upload bandwidth, and 100 people are simultaneously connected to that server and pulling data down, it is possible that your connection speed to that server is 10Mb/100 or 1/10Mbs or 100Kbs. Sadly, it would make no difference what your own bandwidth speed is, and overall throughput is restricted by the slowest link.

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