I've been through the forums and links on tweaking my dsl to get the most out of it with not a lot of luck. I've got cablenut program dl and have tried to input some figures with no success. I've ran speakeasy and avg around 1135 kbps dl and 140 kbps ul. Here's my analyzer info:
OS: XP
TCP options string = 020405a001010402
MTU = 1480
MTU is optimized for Windows XP PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1440
Maximum useful data in each packet = 1440, which equals MSS.
MSS is optimized for Windows XP PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.
Default Receive Window (RWIN) = 63888
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 63888
For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
506880 (MSS x 44 * scale factor of

253440 (MSS x 44 * scale factor of 4)
126720 (MSS x 44 * scale factor of 2)
63360 (MSS x 44)
bandwidth * delay product:
Your RcvWindow limits you to: 2555.52 kbps (319.44 KBytes/s) @ 200ms
Your RcvWindow limits you to: 1022.208 kbps (127.776 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 41 hops
TTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349)= 00000000
Not quite sure what my advertised speed is supposed to be. I use SBC Yahoo DSL if that is any help.
I also noticed in another forum you had some information with a link but I was a bit hesitant to just run the registry without consent. Here's the info in the forum:
OK then your MTU should be 1480, use the following fix from Bob Carrick to set it:
1) Download this file
http://www.carricksolutions.com/XP_MTU.reg2) Right click the file and choose "Merge"
3) Click "Yes"
4) Go to "Start" -> Click on "Run" -> Type in "Regedt32.exe" -> Click "OK"
5) Go to this Reg Key "[HKEY_LOCAL_MACHINE\ SYSTEM\CurrentControlSet\ Services\NdisWan\ Parameters\Protocols\0]"
6) Double click on "Protocol MTU"
7) Click on "Decimal" -> Enter your desired value (I.E.: Anything less then 1480.) Use 1480

Click "OK"
9) Done!
If you have any help you can throw my way to input in the cablenut program to get my dsl smoking I would truely appreciate it. I hope I've given you all the information needed. Thanks!