Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[emgee]

 Having upgraded the firmware of my DG834g v3, I have seen much improvement in my sync speed and SNR. My IP profile went from 3000 to 4000 in a few days. However, real world speed didn't seem to improve. Speedtests were showing around 2300kbps, the same as before the upgrade. Test files were downloading at approx. 265 kb/s. Before contacting my ISP, I tried some tweaks, namely MTU and RWIN. Using DrTCP, I change the settings and rebooted. Then straight back to the speedtests and I couldn't believe the difference! I am now getting around 3800kbps and downloading test files at 470kb/s
Naturally, I'm pleased with the results, but what on earth? Can this tweak really make that much difference? No other changes were made.

[emgee]

I can confirm that it was defintely the MTU/RWIN tweak that made the difference. I followed the same procedure on my daughters PC and got 2047 before the tweak, 3895 after. See here

colour me stunned

For those that are interested, I used 1458 MTU and 153144 RWIN

[Astral]

Brilliant news.

I'm just wondering whether to give my PC another MTU tweak. Hasn't been done for ages and although logic says the settings shouldn't have altered you never know what may have become corrupted over time. I certainly don't get anything like full speed lately, although that is more likely to be down to exchange contention.

[setecio]

Are there not many possibilities of figures to use in the mtu / rwin combo or are there any tools which can work out the best combination to use, or is it just trial and error ?

[Broadband1]

Sorry to sound noobish but how you do MTU and RWIN Tweaks

[Astral]

Here's the MTU link;

http://www.kitz.co.uk/adsl/tweak2.htm


It is largely a matter of trial & error but try Kitz' preferred values first.

[Astral]

Well I've finally got round to re-tweaking my MTU and have gone from 3050 to 6750kbps. Beat that!

I used 1430/166800 on  PC running Windows Me.


I had been blaming exchange contention because my profile is 7150 but I became suspicious that my download speed was always 3000kbps+/- whatever time of day I tested.

[setecio]

Well I've finally got round to re-tweaking my MTU and have gone from 3050 to 6750kbps. Beat that!

I used 1430/166800 on  PC running Windows Me.


I had been blaming exchange contention because my profile is 7150 but I became suspicious that my download speed was always 3000kbps+/- whatever time of day I tested.

  surely this is highly unusual. I always thought MTU/RWIN tweaks only made small improvements at best ?

AH 'win ME' ... would I be correct in saying such a dramatic improvement would be highly unusual for XP or Vista ?

[Astral]

There must have been something badly awry with my PC, I think. I've just run speed tests on my work laptop, running XP, and that shows slightly higher download speed but consistently lower upload. Trouble is we are not supposed to install any unauthorised software on the work machines so I can't try Dr TCPing it. Does anyone know how to change MTU/RWIN manually?

[setecio]

This shows a way via the registry

http://www.windowsreference.com/windows-xp/how-to-manually-set-the-mtu-size-in-windows-xp-2003-2000-vista/

[Astral]

Thanks for that link, Setecio. I think I'll leave well alone rather than get involved in registry fiddling.

Cowards'r'us

[kitz]

Its normally the rwin that can give the speed increases when tweaking on the higher speeds.

>> Does anyone know how to change MTU/RWIN manually?

Dr TCP is actually a stand-alone and doesnt actually install anything anywhere  Therefore you could remove all trace of it and no-one would be any the wiser.  Just think of it as an easy interface as opposed to editing directly via the registry.

[Astral]

Thanks for the info, Kitz, I'll give that a go.

[mr_chris]

Yeah, just run it from a USB disk

[tnp]

surely this is highly unusual. I always thought MTU/RWIN tweaks only made small improvements at best ?

It depends. On high bandwidth high latency circuits, (like a stellite link) the connection can stall waiting for an acknowledgement..opening up the windows there results in much better throughput.

Conversely on channels with packet loss, getting rid of length re-transits is the name of the game, and here breaking it all into smaller chunks is optimal.