PCA Forums

Hi all,

Here's one I've always wondered about:

How come that on my laptop I can download full speed with my 20Mb ADSL, but through the same router I get a max of 5MB file transfer speed from one computer to the other.

So all my computers download full speed 20MB from the Internet, but using the same router on my LAN through Wi-Fi they communicate with each other at a quarter of that speed. ( I haven't tested at what speed they go via cable)

What's up with that? Is that a common issue? It's actually faster for me to download a file from the Internet rather than transfer it from one computer to the other - that doesn't really make any sense!

Cheers

Chris

5MB/sec is actually quite good (unless you mean 5 Mbps...) for wifi. If your router is using 802.11(g), then 54Mbps is the theoretical max, which you'll never reach. 5MB/sec = 40Mbps, so that's good. if you're on (N), then it should be faster, assuming your laptop is also using an N-adapter.

Other things that can slow down wifi:

distance from the router
quality/compatibility of your laptop's wifi adapter
encryption overhead (WPA/WPA2 vs open)...router cpu speed
quality of router
number of wifi clients using the same router
channel selection...RF interference from other routers, etc
general tweaks within the router config. i posted a month or two back on here about wifi speeds with my DD-WRT router...a few tweaks greatly helped my speeds.

.02

Sorry, I think I got my values wrong:

1) on my laptop I download full speed 20Mbps from the Internet using my Wi-Fi connection (well, around 18.5 of the 20 available, but that rock solid)

2) however downloading from another computer on my LAN I only get 5Mbps

Essentially I can download four times faster from the Internet than I can from another computer in my LAN - using the same Wi-Fi connection, going through the same router.

SoI can for example watch streaming video in HD without problems online. But if I streamed the video from my networked PC to my laptop it sometimes chugs because the transfer speed never goes above 5Mbps...

Does that make any sense

Cheers

Chris

You sure you're not confusing MB/s with Mbit/s?

That said, yes, I have noticed that Wifi seems to be inefficient at LAN file transfers - at least older Wireless G technology. I do have clients using N300 speed stuff and they get good performance transferring files from a server.

There's packet loss and reduced bandwidth on both ends. You NEVER get full bandwidth on wireless. Part of that is due to overhead for encryption (unless you're running an open network), overhead for data correction, and bandwidth falls off dramatically the weaker the signal. In your case if it's a file transfer between two PCs that are both on Wifi, you get a double whammy.

I also suspect that 802.11B & G just aren't efficiently designed for NETBios data transfers, but I've never bothered researching it. In my own home, on one of my laptops (using Wifi) I know that it's faster to download an Adobe Reader update from Adobe.com, than it is to pull the update off my own server, unless I plug the laptop into a hard wire.