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Calculate your RWIN !


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yea thats the best thing to do, TCP Optimizer tool from speedguide is great but dosent help all ppl, cos it dosent care how big your bandwith is, only if you got dsl, dialup, cable and so on..............

i suggest this method instead cos too big RWIN on low bandwith will get your connection slower with more packetloss.....

Do like this:

1: run this TCP analyzer http://forums.speedguide.net:8117/

2: find that MSS value for ex:1460

3: run this RWIN calculator http://www.dslnuts.com/bitsbytes.shtml

4: Bandwith is your ISP advertised speed, Latency is your average ping to your isp, Use the MSS value from TCP analyzer.

5: Now you shold have a optimized RWIN value for your connection.

6: download and install cablenut program http://www.dslnuts.com/software.shtml

7: Go to start-programs-cablenut-adjuster in top left corner click open file, browse to ccs folder choose the connection you have and OS ex: cable fast win xp "cable_fast_2k"

8: Now you got a few values set in adjuster, change TcpWindowSize to that RWIN value you calculated before.

9: click save to registry

10: reboot your system

ps if you want to check pingstability and packetloss use this tool, suggest you try it before and after this tweak. http://www.dslreports.com/tweaks

good luck :)

::: Download Stats :::

Connection is: 2950 kbps about 3 Mbps (tested with 1013 KB)

Download Speed is: 360 Kb/sec

Auth Code: 2044251 (validate a http://www.testmy.net)

Bottom Line: 53 times faster than 56K you can download 1MB in 3 second(s)

Validation Link :: https://testmy.net/cgi-bin/auth_check_dn.cgi?num=2044251&kbps=2950&gen=gen

::: Upload Stats :::

Connection is: 2188 kbps about 2 Mbps (tested with 1000 KB)

Upload Speed is: 267 Kb/sec

Auth Code: 282821 (validate a http://www.testmy.net)

Bottom Line: 39 times faster than 56K you can upload 1MB in 4 second(s)

Validation Link :: https://testmy.net/cgi-bin/auth_check_up.cgi?num=282821&kbps=2188&gen=gen

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  • 2 weeks later...

Did anyone test this and how did it work?

all i know 4 sure is that it works great on my 10Mbps fiberoptic connection :)

ps: dont be afraid this Cablenut settings will screw up your registry, in adjuster just click delete cablenut tweaks if your not happy with it, then click save to registry and reboot.

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Happy new year!

To answer your question I have used the tweaks you are talking about, I have found them very useful not only on my machines but on friends and family as well,as a matter of fact I recently formatted my pc and tested with normal settings, after using the optimizer my speed almost doubled. So I'm a believer in using those and other tweaks.As you know as long as you have a good copy of the registry its hard to really hurt anything.I guess its one of those rare deals where you can "turn back the hands of time" so to speak.

8) Microwave^

Live long and prosper!!!

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read this to understand what RWIN is and why you want to optimize it :)


the point is that you might want to use your banwith your paying for on servers that dosent have so good latency.

if you play abit with this RWIN calculator you will soon find out that you need a lower RWIN if you got a low latency to a testsite to get the speed your paying for.

My advise is not to use too high RWIN cos that will result in packetloss and even slower downloading on low latency servers.

Everybody has to test their own optimal settings, cos all is depending on latency.

If you know your goin to download alot overseas with a latency over 100 ms you can increase your RWIN, just use that RWIN calculator.

Read this to find out what bandwith and what latency is :)


good luck :)

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