Why Is My Internet Slow

Jacques du Rand 2019-09-20

Slow internet ? I would not wish that sort of pain on my worst enemy… the only thing that is worse than having a slow internet connection, is trying to convince your ISP that your internet connection for some mystic reason is now slow - even though you have a fast online speed test.

The typical situation:

You’ve got a blazing fast new fibre internet connection you’ve been downloading all the seasons of Friends. You’ve completed all your “Windows Updates” and even uploaded photos of the dog to Dropbox. Then suddenly the connection crawls to a halt...

You’ve tried everything including patience and swearing… restarted the router, the “weird fibre ONT/CPE device” and wondered if you should switch off the geyser, just in case it makes a difference to the endless buffering. Finally, you go out for coffee - you know to let your connection cool down a bit, but nothing helped. You know you are going to have to call your ISP and spend 10 minutes telling the man that doesn’t care that your internet is now slow.


It might go something like this:

ISP: Good Evening - Please do a “speed test” and tell us how fast your line is ?

You: Uhmm hello ja, the online speed test looks good, but everything else buffers and is slow ?

ISP: Well the problem is not on our end.  Are you testing directly from router ?

You: Ja sitting right next to the router…

ISP: Oh that doesn’t matter you need to plug into the router you see…

You: No it’s fast enough according to the speed test. It shows 100mbps, but I can’t browse or stream anything.

ISP: Ah let’s see now…

*lots of impressive sounding keyboard strokes and 5 minute of waiting*  

Thank you for your patience. Let’s just do a quick speed test from the router this time to be sure to...

You: No !!!  It won’t help and that does not explain why I get slow international speeds (Netflix, Google, Youtube, Amazon, Reddit, Browsing) but a fast local speed test.

ISP: Well we can upgrade you to 200mbps if you like ?

You: Why ? For Netflix you only need 5Mbps for HD streaming…

ISP: Oh right right… well let’s do this: Browse to our website and click on the speed test link top right please.

You: Nevermind I am going to kill myself.

ISP: No problem, please rate this call after you are done.


Top reasons your internet is slow, even though you have a fast speed test result:

Local Speed Test.

Most of the popular speed tests in South Africa is testing the LOCAL speed only, yet most of the content we consume, Netflix, Google, YouTube, Email, Browsing is hosted outside of the country. To get that content your connection needs to travel via one of the many undersea fibre cables we have. Sometimes these cables do break, but most ISPs, the best ones, usually have backup routes. This is the number one reason our multi portal speed test is composed of international speed tests not the local one from your ISP. This in our opinion will give you a more honest representation of your current fibre connection status and why Fibre Tiger has the best speed test service.

Slow DNS Service.

DNS is like the telephone book of the internet. It maps names like Vumatel.co.za or Telkom.co.za to their IP Address - the telephone number of the computer.

When you browse to Telkom.co.za - maybe to do a speed test and swear, your computer first needs to lookup that IP address via the DNS service, which at times can be slow.

Some ISPs sends you their DNS service information to use (this all happens automatically most of the time), which is usually not as good as the ones from Google Or Cloudfare. Try setting your DNS to one of these.

You Are Being Throttled

You have reached the maximum download or usage of your connection and your ISP has now throttled your connection. Depending on how your ISP is implementing this stranglehold your speed test might still be fast but everything else slow. Specially if you are on an uncapped fibre package, if you are on a capped package your data will simply run out and you will have no connection usually.

Testing The Wrong Service - Shaped.

When you do a speed test, whether you are on Openserve or on Vumatel this will only test http(s)-protocol basically browsing, upload and download. But when you “consume” data hungry services like torrenting, streaming, Skype calls… it's a completely different service that can be throttled or shaped by your ISP.


Slow Streaming.

If your Netflix or Youtube is slow, yes talk to your ISP (such as Vumatel Or Openserve) about your speed test findings. If your “piracy streaming” is slow its 99.99% the fault of the streaming service, they just don’t have the capacity like the big guys (YouTube, Netflix) to stream to the whole world the latest Avengers - Endgame movie.


The Router And Testing From The Router.

This is the favourite excuse from the ISP:

“You must test from the router itself - Wi-Fi speeds are not fast enough etc”.

Sure they got a point here… most modern routers claim high Wi-Fi speeds like 600mbps+ but rarely achieves this (just physics, interference, sub-optimal conditions). The problem with this is, that, yes, that explains why your 200mbps fibre connection is only achieving 50mbps when you sit upstairs in your room and doing an online “Openserve” speed test, but 50mbps is still 10x more than what is required for a Netflix HD stream. You only require 5Mbps to stream a Netflix HD movie.


Too Many Devices.

This is sometimes overlooked, when it's dinner time and your family of 4, each with a cellphone, and maybe a smart-tv and tablet active as well. That is quite a bit of bandwidth that the Wi-Fi router and fibre connection needs to handle. Try asking that everyone switch off their Wi-Fi and test again.

Even if you live alone it might be a good idea to change the WI-FI password every now and again, unless you keep a strict eye on your router’s connection page, you might not know if you have a bunch of freeloaders on your network. Just don’t make it your street address. “10MainStreet” is not a good password !


Just That Time of Day.

It’s 6pm. Your whole family is at home with their connected devices, but so is your neighbours and their neighbours. It's not uncommon to see degraded performance in peak times. Our advice: pay more and get a higher quality fibre package with less restrictive FUP (Fair Usage Policy) or a better contention ratio.


Too High Contention Ratio:

The contention ratio is how many people “share the same bandwidth-line as you”. Because most consumers don’t use their lines 24/7 it makes sense to share bandwidth-pipes between a few users and just alternate in the background who gets to used it. It's usually seamless and very fast, the problem comes in with high contention ratios like 10:1 or 20:1


Think of the internet bandwidth like a water pipe to your neighbourhood. Not every house will have a pipe directly to the city water supply, you and 5 or 10 of your neighbours probably share an incoming pipe somewhere up the line. Once you add too many houses to this pipe, and they all try to use it at once; these houses will suffer low water supply and pressure. Unfortunately most ISPs don’t publish their contention ratios.


You Got Brainwashed By The Numbers.

So when people say the file is “100 meggs” - what they actually mean is that the file is 100 megabytes big. That is all true yes.


When people say:

“I have a 10 megg line”

Most are actually wrong. They THINK the line is capable of speed of 10 MegaBytes a second, but all consumer connection services are actually being sold as MegaBITS per second.  The difference is a factor of 8 ! The 10 megabits line is in fact only 1,25 MegaBYTES.

It's not as bad as you think though. Yes, your 100MB is not going to take 10 seconds to download, but Netflix HD streaming is still a requirement of 5Mbps (bits). So yes, your 10Mbps will be more than fast enough to stream Netflix. Just don’t get confused or worried when your 100MB(megaBYTE) file doesn’t download fast enough.


Life Tip:

Megabits per second : Mbps(lowercase “b”)

Megabytes per second: MBps (uppercase “B”)

Common Fibre Speeds(Mbps)

Actual Speed in Megabytes(MBps)

10 Mbps

1.25 MB/s

20 Mbps

2.5 MB/s

40 Mbps

5 MB/s

100 Mbps

12.5 MB/s


Bottom Line

Don’t be fooled by fast local speed tests. Use an international speed test service like the one on our website