Question about WLAN speed

I

IsaacMM

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Jun 9, 2008
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I have a contract for 100 Mbit/s and I get the full speed if I connect via cable. If I use Wlan though, the most I get is 40 Mbit/s.

I have a 2 in 1 modem/router, which supports up to 150Mbps wireless speed. I also contacted my internet provider and they confirmed that the devide can support a 100M wireless speed. It is configured to 802.11n

The wireless adapter in my computer also supports 802.11n and speeds up to 150.

What could be the reason for this low wireless speed? I tested with the computer really close to the router. When I asked the technical support, they said they can't guarantee the full wireless speed because ''it depends on many factors''.

Would appreciate any help.
 
you're experiencing loss via wifi. many things can affect it including noise, transmit strength etc.
 
IsaacMM said:
Is it solvable? If I buy a more expensive router or a better wlan adapter, for example.
Click to expand...

Consider this... The absolute MAXIMUM your current WiFi setup can achieve is 150, which is likely only achieved in a lab somewhere. Once you get into actual homes with competing signals, db loss at range, and other wireless devices, your throughput drops fast. Also those two in one router/modem combos very often don't have the greatest WiFi gear inside. Getting 40 during real world use seems reasonable since there is a lot factors that slow down WiFi and you are using what appears to be older low end gear.

If you want to consistently get 100 wireless speed, pickup an AC WiFi router and a matching adapter for your PC. AC will use the less crowded 5GHz signal range, however the 5GHz signal is more affected by long ranges and walls. This will cost you $100+ and you may not notice a difference in actual use.
 
Ocellaris said:
Consider this... The absolute MAXIMUM your current WiFi setup can achieve is 150, which is likely only achieved in a lab somewhere. Once you get into actual homes with competing signals, db loss at range, and other wireless devices, your throughput drops fast. Getting 40 during real world use seems reasonable since there is a lot factors that slow down WiFi.
Click to expand...

Ok I guess I was just really ignorant about how much a Wifi signal can be affected and its limitations. I knew it wouldn't be the same as cable speed but I didn't expect a more than 50% drop.

Thanks for the explanation.
 
Wi-Fi isn't all the magical unicorn farts that people hype it up to be.

Wi-Fi is a tool and like any tool has its place and uses.
 
I work for a telecom company and we test consumer devices for performance.

The maximum speeds listed on manufacturers isn't even what the device itself is capable of, it's what the TECHNOLOGY itself is capable of. There's two things we test for, max throughput, and something else we call max goodput.

Goodput is the actual data you are receiving, thing like TCP/IP overhead, processing overhead. So what you are seeing when you are transferring files back and forth between your computers, or a speedtest site is goodput which would be the lowest of the 4.

The 4 being, in order of highest to lowest

1. What the technology is capable of (e.g. 802.11 AC is capable of 1.4 Gbits/sec) <-- this is what is manufacturers ALWAYS list as their "max throughput"
2. What the device is capable of (after processing overhead due to CPU, chipset, etc.)
3. Max throughput (this is the rate where the two devices can talk to each other, subject to distance, interference from other wi-fi and environmental radiators like microwaves, cordless phones, wireless cameras, wireless baby monitors, etc. Remember even your neighbours wireless devices will affect your in home wi-fi)
4. Max goodput. This is the ACTUAL throughput your computer sees.

In our lab when we test wi-fi devices, one of the tests we do is to get max throughput of the device. We connect a copper cable to the device to our test unit and seal it in a radiowave proof chamber. That way we take out any possible environmental radiation out of the equation. Even then we don't ever get what the manufacturers list as their max rate.

All in all, I blame Marketing for disillusioning the customer to what to expect from wi-fi.
 
25 feet and one wall away I can barely get 10MB/s from a Linksys EA6350 and an Intel 7260, both AC/5GHz. Windows will always show a 290-500Mbps connection speed to the router, but any local file transfers from my computer to my server (connected over gigabit ethernet) cannot break 1/5-1/3 that.
 
From my experience, I usually take the speed and divide by 3 in best case scenarios. Add in competing wireless users, interference, walls, RFI, etc and often times you are at 10%.

I can get ~15-20MBps transfers on an Intel 7260 with pretty much direct line of site on a nighthawk R7000 both on AC. Once I go downstairs or too far away it drops to 5-10MBps
 
Most wired connections can do duplex communications. Meaning both sender and receiver can transmit at the same time. Most single channel wifi is simplex. One transmits and one listens. Instant drop of speed from listed theoretical to real world of about 1/2. Add in overhead and you get the 1/3 rated speed mentioned by charold. Add a second wifi client and it gets worse. Now add in loses due to walls, nearby neighbor's wifi, other gizmos using the same frequencies and you start getting the results you are. This is why many newer wifi routers have multiple radios and even dual band.

If that 40Mbits is reliable, consider yourself lucky.
 
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