Old 03-14-04, 12:55 PM
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john 3:16
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Talking sb31000

could someone tell me what the BEST registry settings would be to get the maximum speed out of my sb31000 cable modem. upload and download. here is what i am running right now, courtesy of

TCP options string = 020405b4010303030101080a000000000000000001010402
MTU = 1500
MTU is fully optimized for broadband.
MSS = 1460
Maximum useful data in each packet = 1460, which equals MSS.

Default Receive Window (RWIN) = 372296
RWIN Scaling (RFC1323) = 3 bits (scale factor of 6)
Unscaled Receive Window = 46537

For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
513920 (MSS x 44 * scale factor of 8)
256960 (MSS x 44 * scale factor of 4)
128480 (MSS x 44 * scale factor of 2)
64240 (MSS x 44)
bandwidth * delay product:

Your RcvWindow limits you to: 14891.84 kbps (1861.48 KBytes/s) @ 200ms
Your RcvWindow limits you to: 5956.736 kbps (744.592 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = OFF
Time to live left = 117 hops

TTL value is ok.
Timestamps (RFC1323) =
Timestamps (RFC1323) = ON
Note: Timestamps add 12 bytes to the TCP header of each packet, reducing the space available for useful data.

Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000

thanks DALE
Old 03-14-04, 03:44 PM
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I have NO IDEA what any of that is. Where in the registry dp you find that? I didn't even know there was a "setting" for maximum cable modem speed. My guess is that these settings have little, if anything to do with your cable service performance. I don't see how they possibly could...

Simply put, your cable company should pipe your download speed as fast as possible. Most providers, however limit your upload speed (generally to 256k).

Old 03-14-04, 05:38 PM
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Go to DSLReports.Com and run the tweak tests there, or download an internet tweaker to do it for you - get one from Download.Com. That's going to be the easiest way to make the changes.

Most tweakers will set the settings for you, according to the speed you select (56k dial-up, Cable, DSL, etc.)

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