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I have two WiFi connected computers via a WiFi modem/router to share my internet connection. This setup works fine to access the internet but I am not able to effectively transfer files between these two computers. The maximum speed is around 300 KB/s and it fluctuates a lot (generally going downwards). Sometimes the download even stalls. Is there something wrong with my Wifi drivers?

All my wireless devices are capable of 54 Mbps connectivity. I don't see anything near it while transferring data over my WiFi router to the other computer. Has anybody else seen better performance?

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Please add details of your wifi cards. Also - which computer is having the issue? i.e. connect one computer via a router using a fixed ethernet connection and the other via wifi. Then swap around. The slowest obviously is the one you want to concentrate on. –  fossfreedom Sep 5 '11 at 20:06

1 Answer 1

up vote 3 down vote accepted

The 54Mbps is the upper bound, and in that 54Mbps, a percentage is overhead even with no other devices.

Full duplex wired networks can also have all devices connected to a router communicating at once...on a wireless network, only one device can talk at a time, and the way they do it is by checking to see if there is anything else signalling, and if so, they wait for a random length of time before trying again.

So with your laptop and an access point, that is already two devices sharing the bandwidth. Anything else on that frequency, or even near it, and you will get increased retries, collisions etc.

Even turning your microwave on may affect it, depending on just how good the shielding is.

You also should realise that bps is not the same as B/s - a Byte is 8 bits, so 300KB/s is 2.4MB/s of data, plus a few hunderd K of overhead - so it isn't quite as bad as you think:-)

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I have a 54Mbps card in my laptop and was connected to 80Mbps router and I could just come up to 40Mbps in speed down/up. the internet speed was 100Mbps. Other people with better hardware at the same time could get up to 75Mbps. –  Alvar Sep 5 '11 at 20:57
    
@Alvar - that seems reasonable too. The OP probably needs to carry out a wireless survey to see what else is around. –  Rory Alsop Sep 5 '11 at 21:10
    
300*8 = 2400, not 1800 :) But, as a matter of fact, "bits per second" also includes various control bits, packet headers etc. which are transferred "on top" of the actual data. Which means that if file download speed is 300 kilobytes/s, the actual link speed is closer to 3-and-something megabits per second. –  Sergey Sep 6 '11 at 1:45
    
Thanks @Sergey - updated my numbers. –  Rory Alsop Sep 6 '11 at 7:36

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