Disable Windows Vista TCP/IP Auto-tuning

2011.0830

Let's face it every so often you have to tweak your computer because it suddenly starts behaving badly; sluggish performance, lock-ups, freezes, etc. Often it's because one of those "helpful" updates to your operating system or other software left broken or dead entries in your Windows Registry. The same thing can sometimes happen when you install upgrades or uninstall software. The solution usually involves running a registry cleaner to repair or remove the entries.

Other times, the problem requires a bit more work. Here are just a few of the possible causes of problems:

• network hardware such as the modem, router, cabling, or your computer's network card can be faulty
• network software for the modem, router, or your computer's network card can require an update or an upgrade
• settings, such as those for TCP/IP can require tweaking for hardware or software changes
• new hardware and software can be incompatible with your existing equipment and system

If you have Windows Vista (like me), you have had to contend with Microsoft's User Account Control (UAC) and Data Execution Prevention (DEP) software; this can prove highly frustrating at times. If you bought your computer in the early days of Vista, you may have also had to buy new hardware because your perfectly good "old" hardware (such as your printer or external hard drive) would not work with your new computer's operating system (OS). In my case, the peripheral hardware manufacturer decided not to produce a driver to work with the new OS. My only solution was to replace the hardware.

Now, years after purchasing my computer, I still find it necessary to perform tweaks now and again. Okay, so that's to be expected. What is not to be expected is the freezes and crashes I suddenly started experiencing some time ago.

All of the sudden, Outlook became even more obtrusive than usual. Programs such as Adobe Acrobat, Microsoft Word, and Internet Explorer (IE) would suddenly freeze as soon as Outlook started to check for incoming email. Crashes were beginning to occur with no warning and no indication of the reason. Network connection timeouts were happening with increasing frequency.

These problems didn't start all at once. On the contrary, the problems began appearing only occasionally, but the frequency increased over time. When the problems were at their worst, they increased suddenly and dramatically to the point that they had a major impact on my ability to perform and produce using my computer.

At first, I blamed software -- specifically, my recent upgrade to IE 9 and my recent upgrade to the newest version of QuickBooks software. This blame was not necessarily misplaced. IE 9 beta caused me enough problems that I finally uninstalled it and had only recently (and reluctantly) reinstalled the "ready-for-prime-time" version (everything seems okay now). As for QuickBooks, I had recently spent over seven hours on the phone with technical support about a particular aspect of the QuickBooks upgrade that appeared to be hogging free memory (this has since been fixed) in a case of good intentions producing the wrong results.

Finally, after trying everything I could think of, I began researching from a different direction and stumbled on what appears to have been the answer: Windows Vista Auto-tuning.

What is Auto-tuning? It is a feature of your operating system that monitors network conditions and attempts to adjust the TCP/IP receive window size accordingly.

Unfortunately, it may prove incompatible with some network hardware (such as certain makes and models of router). In my case, this appears to have been the problem; I had recently purchased a new router to replace an older, defective one. As usual, troubleshooting involved weeding out all the variables. Only after ruling out the software changes previously mentioned did I remember the network hardware change and realize it might have had an undesireable effect. Once I disabled Auto-tuning, most all of the problems disappeared.

Here's how to disable Auto-tuning:

1. Click the Start button, search for command, right-click the icon and left-click "Run as administrator."
2. In the Administrator Command Prompt window, type netsh interface tcp show global to see if Auto-tuning is enabled.
3. If Auto-tuning is enabled, type netsh interface tcp set global autotuning=disabled to turn it off.
4. Repeat step 2 to make verify Auto-tuning is now disabled.
5. Type netsh interface tcp set heuristics disabled to prevent Vista from overriding your settings.
6. Type netsh interface tcp show heuristics to verify step 5 was effective.
7. Type exit to close the Administrator Command Prompt window.

That's it. Hopefully, you'll see the same computer performance improvement I did. Be sure to note, however, that changing these settings may cause problems for faster broadband connections. If it does, repeat the steps above and substitute "enabled" for "disabled."