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Broadband Internet Connection Tweaking

Posted September 2003 by Steve Sinchak

If you are reading this then you are looking to maximize your bandwidth by tweaking your computers registry and other settings. There are a few things you must know and understand prior to optimizing your connection.

•    Your goal in tweaking is to get 90% of your ISPs bandwidth caps, but remember that sometimes due to factors beyond your control such as routers, nodes, distance from your CO or congestion etc. you WILL NOT obtain that goal.

•     You need to know your ISPs caps in kilobits, for example I have Cox Internet Service and my caps are 3000/256. This information is usually found on your ISPs website.

•     You need to download CableNut from here, it is the most comprehensive internet connection tweaking app available.

•     You need to know what your maximum anticipated latency is by following the instructions here.

•     Once you know what your ISPs caps and your maximum anticipated latency are you just need to input it into the CableNut Live webpage. Our own Moderator here j79zlr made this page and it uses the proper formula for finding all you optimum registry settings.

•     You need to make sure your MTU (maximum transmission unit) is set properly since other settings are based on this, to check yours do a TCP/IP Analyzer Test. This will tell you what your current TCP/IP registry settings are. The proper MTU values are as follows, make sure yours is set accordingly: Cable – 1500, Normal DSL – 1500, PPPoE DSL – 1492, XP Native PPPoE DSL – 1480.

If you are using XP's native PPPoE setup and your MTU is not set to 1480 then copy and paste the following and make it a .reg file and merge it into your regstry to correct it:

Windows Registry Editor Version 5.00




•     It is important to test your speed properly, the most accurate test is to download a large file from a fast reliable FTP server such as the following two:



RoadRunner FTP Test (Tampa FL)

Another fairly reliable test is from Speakeasy, it is a java based test and isn’t as accurate but if you do multiple tests from around the US it will give you a fairly accurate result. Here is a full list of their test sites:

New York City
Washington D.C.
San Francisco
Los Angeles
Minneapolis/St. Paul

Make sure you clear your browsers cache prior to each test.

For all the definitions to the values in CableNut read here.

The Windows 2000 White Papers – The official Microsoft papers on how TCP/IP works in Windows 2000 & XP.

Along with properly optimizing your TCP/IP & AFD values there are also a number of other things you can do to help maximize your bandwidth.

•     Setting your NIC (Ethernet card) duplex mode properly. Duplex modes are as follows:

Cable Modem – 10mb half duplex*
DSL – ISP dependant
If using a router set it to 100mb full duplex.
*OOL users should set their duplex mode to 100mb full duplex

To set yours do the following:

Open your control panel – select the network icon – right click on your LAN connection and select properties - under the ethernet adapter icon click the button configure - select the advanced tab - in the property box, the property name to be selected varies according to model of ethernet card. Examples are: Network Link Selection, Media Type, Connection Type, Duplex Mode, or any similarly named property which can have Values looking like Auto-Negotiation, or 10BT, or 10BaseT - in the Value box, select a value which either (a) explicitly says half-duplex or semi-duplex, or (b) at least does not say full-duplex [e.g. 10BaseT on its own is OK] – if there is a choice between 10 and 100 with half-duplex, choose the 10. Do not choose 10Base5, 10Base2, or AUI - click OK to exit the Adapter settings - click OK to exit the connection properties.

•     Setting your TCP/IP metric setting properly, it should be set to a value of 1. To do so do the following:

Open your control panel – select the network icon – right click on your LAN connection and select properties – highlight Internet Protocol TCP/IP and select properties – advanced – select the IP settings tab – in the interface metric box put the value 1 – ok.

•     Speeding up network browsing.

Open regedit and navigate to:


Delete the key: {D6277990-4C6A-11CF-8D87-00AA0060F5BF}

•     Faster webpage tweak by giving priority to DNS lookup.

Copy and paste the following and make it a .reg file and merge it into your regstry:

Windows Registry Editor Version 5.00



•     Forward buffer memory tweak, this controls how much RAM TCP/IP uses for storing packet data in the router packet queue.

Copy and paste the following and make it a .reg file and merge it into your regstry:

Windows Registry Editor Version 5.00



•     By default Windows 2K & XP cache everything in the DNS cache service, both correct and faulty DNS lookups. To increase performance by eliminating the caching of faulty DNS lookups, copy and paste the following and make it a .reg file and merge it into your regstry:

Windows Registry Editor Version 5.00



•     Internet Explorer important settings:

Open Internet Explorer and select Tools - Internet Options - under the General tab in the Temporary Internet files section select the Settings button.

Select "Every visit to the page" and set the amount of disk space to use: to no more than 80MB. Now select the Connections tab and select LAN Settings make sure EVERYTHING there is unchecked and select OK.

For IE6 ONLY - select the Privacy tab and choose Advanced check the box "Override automatic cookie handling" and for First-party Cookies - Accept, Third-party Cookies - Block and check "Always allow session cookies. Now NO MORE SPYWARE COOKIES.

Another thing to do about once a week if you modem is on 24/7 is to power cycle your modem, just completely disconnect power from it for at least 15 seconds and then power it back on.

Set your temporary internet files to 80mb and delete them regularly.

•     DSL users may want to check out the DSL Wiring Guide for possibly increasing your DSL speed.

DSL users also want to make sure they do not have any halogen lights close to their modems or 900mhz or 2.4ghz phones in the same room.

•     Always connect your modem via ethernet (Network Interface Card) instead of USB, ethernet is faster and much more stable. Also ALWAYS make sure you have the latest drivers for your NIC from the manufacturer NOT Microsoft, usually the drivers from the manufacturer have advanced settings that help optimize the performance of your NIC that the native Microsoft drivers don't have. If you are using a router always keep your firmware up to date.

•     Remove any uneeded protocols:

Open your control panel – right click your LAN connection - properties - general tab, uninstall all the protocols there that you do not need. If you are a stand alone pc then all you need Internet Protocol TCP/IP. If you are on a network then you will need them except QoS Packet Scheduler, it is never needed.

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