For an explanation of the terms used, Click Here.

Before beginning this exercise remember to back up your registry .
You might make a mistake and ......

Add MaxMTU to your Registry
In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\NetTrans\000x
where 'x' is the number for your modem (you may see several numbers [0001, 0002, etc.] it seems to be safe to put this entry into each of them if you're not sure which one to use. You can also look through each and see which one holds your IP number of your modem.

Add MaxMTU as a New String Value
Give it a value of 1500

How To Determine Your ISP'S MTU
1500 MTU's is used by most ISP's using cable modem. The optimum MaxMTU is actually determined by you ISP, here's a way to determine the optimum MaxMTU setting.
Open a DOS Prompt window and enter the following command until you know exactly which is the largest packet size that doesn't get fragmented:
C:\> ping -f -l [packetSize] [www.localisp.com]
where [packetSize] is the size of the data packet you will send (only use values between 0 and 1500) and [www.localisp.com] is the URL of your ISP.

The biggest value that does not give you the error "Packet needs to be fragmented, but DF set" will either be the MTU of your ISP, or their MTU-28 (without the header), depending on the server settings.

Windows will then automatically set the MaxMSS setting to (MaxMTU - 40), which is 1460, you could add the value yourself too.

Add DefaultRcvWindow (RWin) to your Registry
In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP
Add DefaultRcvWindow as a New String Value
Give it a value of (Win95 64240), (Win98 372300)

Add DefaultTTL (Time-to-Live [TTL]) to your Registry
Windows uses a default TTL value lower than the rest of the computing world. If a Web site is too far away for the TTL you can't talk to it at all. The connection attempt to the site times out. If you can talk to the site at all then any timeouts after that are not related to the TTL.
In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP
Add DefaultTTL as a New String Value
Give it a value of 128

Add BSDUrgent as a New String Value
Give it a value of 1

Add PMTUDiscovery as a DWORD decimal value
Give it a value of 0 (00000000)

Add PMTUBlackHoleDetect as a DWORD decimal value
Give it a value of 0 (00000000)
Close Regedit and reboot.

There are also some settings that help speed up Web Browsing
In Regedit go to:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\
Add MaxConnectionsPer1_0Server as a DWORD decimal value
Give it a value of 10 (00000010)
Add MaxConnectionsPerServer as a DWORD decimal value
Give it a value of 8 (00000008)

The following registry tweaks are for Windows 98 and above ONLY:
In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP
Add Tcp1323Opts as a New String Value
Give it a value of 3

In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP\Parameters
Add SackOpts as a New String Value
Give it a value of 1

Add MaxDupAcks as a DWORD decimal value
Give it a value of 3 (00000003)

The following registry tweaks are for Windows 98SE ONLY:
This deals with optimizing Internet Connection Sharing in Win98SE.
In Regedit go to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ICSharing\Settings\General\
Add/Change the String Value internetMTU
Give it a value of 1500 (if this was your MTU discovery amount in the first part of this exercize)

System.ini Network Card Tweak

In Windows 9x, you can reserve specific amounts of RAM for specific IRQs (Interrupt Requests), which serves as a buffer to allow more stable operation of your device. Adding a 4Mb buffer to your Network Card's IRQ would ensure good overall performance and increase throughput with broadband Internet connections, such as DSL and Cable Modems.

Reserving RAM for your Network Adapter might prove very useful, especially during CPU intensive tasks, or while gaming online. For those with 500MHz or slower processors and 128Mb or less RAM, this tweak might show noticeable results at all times, including faster displaying of web pages and higher throughput. Even with fast processors you will get better overall performance, including smoother stream video, better transfers anywhere from 0 to 10%, with more noticeable results during faster transfers. Another good reason for using this tweak would be if you have a PCI NIC sharing IRQs with another device.


Step 1 - Find your Network Card's IRQ

In order to add the entry to your System.ini file, you'd first have to find your NIC's IRQ.

Right-click on My Computer icon on your Desktop, then left-click on Properties (a shortcut for that would be to press the 'Windows' + 'Pause' keys). Navigate to Device Manager and double-click on Computer. Under "View Resources" you will find a list of IRQs, each with description of the device that's using it. Note the IRQ number used by your Network Adapter.

Adding the entry to System.ini

Once you've found the IRQ of your Network Card, you need to reserve some RAM for its use, by adding an entry to the System.ini file. You can edit the file in any text editor, however the easiest way is to use Windows' built in "System Configuration Editor".

Navigate to Start > Run and type sysedit. Find the [386enh]Section in the System.ini file and add Irq[n]=4096 under it, where [n] is the IRQ number of your NIC and 4096 is the amount of RAM you want to reserve in Kbytes. i recommend using 4096, however you can experiment with different values if you want. Save changes in the file, exit and reboot for changes to take effect.

Note: If you choose to try different values, keep in mind that reserving too much RAM for your NIC will decrease the amount of RAM available for applications, while reserving too little might not give the desired effect.


Additional Thoughts

The only negative effect of the System.ini IRQ tweak is that it will reduce the amount of RAM available for running applications a bit, by reserving some specifically for your Network Card's use. The gain in performance usually outweighs the negative effect by far, considering any Computer with 32Mb of RAM or more.

Keep in mind that if you add hardware to your system the IRQ of the Network Adapter might change, in which case you will need to modify the setting in System.ini.

In systems with multiple NICs, you might want to add the setting for both IRQs. Also, you could reserve RAM for other IRQs if you wish, just use common sense and don't forget it reduces the amount of RAM available for running applications.

If you are using an USB device, it does not have a specific IRQ, however you can try adding the entry using the IRQ of the USB Controller.

For internal Cable Modems, you'd have to add the entry using the IRQ of your modem, rather than the IRQ of a Network Card.

Hope this helped out speed things up a bit.

A majority of the information found on this page is resoursed from SpeedGuide.Net

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