Drop in Wireless Speed

I am trying to solve this annoying puzzle. I would appreciate any help! Over the last couple of days I have noticed that while my ethernet speeds are what I expect them to be - around 6mbs - my wirless speeds have dropped by about half of that

. I have tried two different routers - a BT HomeHub 2.0 and Netgear DG834N and both with and without encryption, but the results are the same. I

have even added a Belkin wireless adaptor to my laptop, but still no joy! What could be the problem?

P.S I noticed that there are a lot of wireless networks active this weekend - even more than usual. Could that be the reason?

Interference from other users can affect your speeds. You could try using a different channel.

Have you measured your radio throughput before. If you haven't perhaps it's always been lower. If you are using Windows XP try the freeware TCPOptimizer to tweak your settings.

See http://www.speedguide.net/downloads.php

Thanks for your prompt reply John. I have solved the problem - it was the rwin setting. I carried out a tcip repair and did not realise it caused my rwin settings to revert back to default. I raised them again and speeds are back to normal again Amazing how both Netgear and Belkin technical support never suggested that.

Edited by deleted (Sun 26-Jul-09 00:47:36)

I have exactly the same problem - noticed it last night !
Wireless speed on the laptop dropped from the usually rock steady 10 Mb/s to around 4 Mb/s consistently.
No changes made during this time but double checked router settings (Linksys WAG200G) and also laptop wireless settings (Intel 54 Mb/s wireless G Dell laptop card)
Hard wired ethernet from laptop to router gives normal speed of 10 Mb/s - so it can't be my ISP (O2)
Wireless speed on another desktop PC running Windows XP SP3 is as usual (10 Mb/s) from the same router so it can't be the router that is faulty.
Laptop also runs Windows XP SP3 - 17 July was the last day I tested speed on the laptop and obtained ~ 10Mb/s.
I ran anti-virus and found one trojan - which was removed. Also restored laptop back to 17 July but still got the same low wireless speed.
Tried different sites for speed testing and still obtained ~ 4 Mb/s

I'm wondering if there was some windows update or some other virus during the last 48 hours - as only the laptop was used during this time.
Anything else to look for ?

You could try my suggestion below - use DrTCP and tweak RWIN and MTU settings. I have found the effects to be remarkable.

P.S See my post below. ("Massive Speed Gain Through Raising RWIN")

Edited by deleted (Sun 26-Jul-09 00:43:06)

Thanks. I've used Dr TCP and TCP Optimizer for many years and also checked again to see if RWIN/MTU values were somehow changed but they are still the same as before.
So my lower speeds are still a puzzle !

Sorry to hear that - I was hoping my solution would work for you.
(My experience is that persevering in investigating the source of the problem eventually pays off - at least till the next issue arises!)

Any positional change to either device. Any new obstruction. Any new source of electrical noise. Is this pairing closer to a neighbour using the same channel?

In reply to a post by john2007:

Interference from other users can affect your speeds. You could try using a different channel.

Have you measured your radio throughput before. If you haven't perhaps it's always been lower. If you are using Windows XP try the freeware TCPOptimizer to tweak your settings.

See http://www.speedguide.net/downloads.php

No, it won't be interference - wi-fi is a service designed to have may users on a given channel. If it wasn't, then wi-fi hot spots and wi-fi in hotels would not work. What can happen is a slow-down caused by lots of users using the channel at high throughput.

I suppose "other users sharing the same channel" might have been better than "interference from other users". Mind you interference has several meanings and the overall phrase is shorter.