Your advertised DL speed will be more than you are showing in most tests. I.E. a Speed Test result of 3.85Mbps is what most will show on a 4meg down service. So my advertised speed is 4000Kbps or 4.0Mbps
When the "RESULTS" button lights up then click it to go to the next page.
Select your "SERVICE" then under your "SPEED" (advertised) enter 4000 (for 4.0 meg down) 5000 (for 5.0 meg down) ect. Your OS; then under "CONNECTION" in most cases you will select "NORMAL". If you use a "USER NAME" and "PASSWORD" then you have a "PPPOE" type connection. "ROUTERPPPOE" is used if your "USER NAME and PASSWORD" are setup in your router. "RASPPPOE" and the others you will know if you are using them. Otherwise select "NORMAL", then click on "RECOMMEND".
This page will display (under your tweakable settings) What your TCPRecieve window and other settings as they stand now. Get a pen and paper as well as a calculator.
Write down your MSS requested. In most cases this will be 1460. If not then make a note of it. Now; on the bottom left of the page in blue text you will see "MORE DETAIL", click it. Now go to the bottom of the page and note your RTTavg: click link for example: http://photo-origin.tickle.com/image/146/5/1/O/146513554O646716174.jpg
Now: Here is the formula to use.
Your RTT avg x 1.25 x your advertised download speed = ??????? that total ??????? devided by 8 and that total divided by your MSS requested = ??.??? Round that number up the the next whole number and multiply it times your MSS Requested = What your TCP recieve window should be set at.
For example: If my RTT avg is 80.3 and my MSS requested is 1460 and my download speed is 4.0 meg (4000).
80.3 x 1.25 = 100.375 100.375 x 4000 = 401500 401500 devided by 8 = 50187.5 50187.5 devided by 1460 = 34.375 Round up and you get 35 (you can use 34-35) So 35 x 1460 = 51100
So my ideal TCP Recieve window is 51100
To set it you will use the DRTCP you saved to your desktop. Open it up to make the changes and "SAVE" when you are done.
{You must reboot your system for changes to take effect}
Other things can help you as well. Set as follows:
Window Scaling = yes Time Stamp = No Selective Acks = Yes Path MTU Discovery = Yes MTU = 1500 <<<<(only for cable and DSL) {some DSL may be less than 1500 but it will default to the proper one either way}
NOTE: Some of you on 5meg and above may see a decrease in Download speed when using this formula if you are close to a NODE or have little network traffic in your area. If this is the case then increase your TCP Recieve window by adding your MSS requested to it and "SAVE" it. Example: 51100 + 1460 = 52560 You would try 52560 as your new size. Do this untill you see your speed where you think it should be but you do not have warping or cant respawn issues. If you have those issues then you have gone to large.
And for those of you who have Dialup! Use the same tool and set Your TCP Recieve window to 2981 and your MTU and your Dialup RAS MTU to 576. Change only those settings and everything else to default.
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