Wifi is susceptible to interference from other wifi sources which can cause reduced performance. Some routers can dynamically change the frequency of the wifi but in some cases, this can cause the devices to momentarily drop and then reconnect to the wifi. While in most cases this would not be noticeable, some devices such as games consoles that can have persistent streams of information coming through to them, may notice breakup in the gaming experience.
5 GHz wifi is capable of much faster speed that the original 2.4 GHz wifi however it does not have the same coverage area as the 2.4 GHz wifi does. Although 5 GHz is faster, you may not be able to realise the full potential of your internet connection via the 5 GHz wifi as the performance of it is very much dependent on the performance of the wifi card inside your device. For example, if you have a 1000 Mbps fibre internet connection coming into your house, but your wireless device is only capable of 600 Mbps then you will not be able to avail of the full 1000 Mbps on that device.
Wifi Contention is caused by having multiple devices all connected to the wifi at the same time. The wifi on the router has a finite capacity and the more devices that are connected at the same time, the more that finite capacity is having to be shared amongst them all. To reduce the contention on your wifi you should switch off devices that are not being used.
Internet Contention is something over which you have no control. The maximum number of customers connected to the local exchange is governed by the owner of the exchange. They will have designed their network so that, under normal loads, there is more than enough capacity for everyone to use the internet. However there may be times where the loads on the network are higher and as a result, you could experience reduce throughput. You can think of it as being like a motorway. For most of the time there is enough space on the motorway for everyone to travel at the speeds they require (subject to the speed limits in place). However there can be times when there is more traffic on the motorway than there is space for it all to fit, and traffic then slows down (just look at the M50 at rush hour!)
Service Contention often happens when there is high demand on an online service (such as streaming services) but the service does not have sufficient capacity to handle the level of demand. Most legitimate services can dynamically increase their capacity based on the demand they are expecting however some services do not have this capability and then can be affect by demand for their service out-stripping supply.
- The capability of the device on which you are running the speed test (i.e. if there are processes running in the background this can affect the result)
- The level of usage on your connection at the time the test is being run (i.e. if your other devices are actively or passively using the internet connection then a portion of the bandwidth is being used by them which cannot then be used to ascertain the speed test result)
- The amount of traffic on our network (i.e. at busier times, there will be more traffic on our network which could affect the results)
- The capacity of the internet connection to which the test server is connected (test servers are hosted by various companies and some companies will have higher bandwidth capabilities that others)
- How many other people are running speed tests to the same server as you (the more demand there is on it the more delay it could introduce to the results it is sending back)
- Before running a speed test, make sure that nothing else is using the internet in your household, ideally switch off all devices so that nothing else is connected except your device
- Make sure that the device you are using has the capability to achieve the maximum speed of your internet connection (for example do not use a laptop that only has a 100 Mbps network port on a fibre connection that can go at 500 Mbps)
- Connect your laptop using a suitable ethernet cable, as running a speed test across the wifi can introduce other issues into the equation
- Make sure that there are no processes running in the background on the laptop that could affect the result (for example, there are no updates running nor virus scans or other Windows processes running that could be using large amounts of processing capability of the laptop).
- Make sure that you are running a test to a server that is located close to you (you don't want your speed test to be bouncing half way round the world and back again)
The way in which information is packaged and transferred across the network, especially fibre connections, typically results in a loss of between 8 and 10% of the maximum capacity of the connection. This is not a fault, so speed test results will always appear to be less than the maximum available.