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Information on 'Tweaking' your TCP stack

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Tweaks : Can you max out your connection speed?

Your PC may not be tuned properly to take full advantage your full connection speed. For those with high speed connections (faster cable networks, FiOS, etc), tuning your TCP stack is necessary if you wish to fully utilise the available bandwidth in one single download.


Windows XP used to have issues running fast over higher latency connections hence the whole "Tweak" business grew online with tools like this and many others. More recent versions of Windows, as well as Linux and OSX and mobile devices do a good job of automatically optimising connections, and "tweaking" is just not required or in the case of Windows, even particularly easy to do. Modern broadband connections tend to get used by many services at once and tweaking a connection for higher top speed was always about optimising a SINGLE transfer.

With the advent of consumer 100 to 1000 megabit and beyond connections, speed tests (which were used to "test" tweak effectiveness) now need to run multiple streams and this obscures any change in single transfer speeds.

If you work in academia and have need for high speed single-stream transfers over long distances you can find better guides online for TCP modifications that can increase the speed of such transfers beyond the already high limits the modern OS imposes - but usually these come at the expense of the reliability and flexibility of local transfers.

Too Long - Didn't Read : the tweak testing tool is retired

Our tweak tester will monitor a test download and then suggest which settings you should modify, and why.
Tweaking may fix
Slow download speeds
Download slower than upload speed
Skipping in TCP streaming video/audio
Connection issues to some sites
Tweaking will not fix
Packet loss
Multiplayer games over UDP
Your ping time
PC freezes

Java Tweak Tool

Attention Satellite Users: DO NOT USE THIS TOOL - instead read the Satellite User FAQ on the subject of TWEAKING, also check out the Direcway Satellite Users Forum

«« No JAVA APPLET displayed? Please see FAQ entry 309: "the JAVA applets do not work"

«« BUSY? The tester is limited to certain maximum number of simultaneous tests at a time. It is also limited to 5 tests on one IP within a few hours.

The usual problem is that one or more PC 'security' programs (Zone Alarm PRO, Norton etc) are blocking this tool, and not alerting you. Disabling them should enable the test to function correctly.

Please make sure your browser can make requests to port 8085 and 8086. A firewall installed on your PC may block web requests to all ports except 80 and 443 without pop-up notification. This will halt the tweak test.