Vista Probs - Slow Internet Speed

I had a phone call from my younger sister today - her fiance's PC was running strangely. Sometimes the internet was fine, other times it ground to a halt. They'd checked for spyware and viruses - but couldn't find anything wrong.

Whilst logged in as an administrator open a command prompt (or use the "run as" option on the command prompt shortcut).

Type the following command:

netsh interface tcp show global

This should return a fair bit of information, but the line we are interested in is the one that starts:

Receive Window Auto-Tuning Level

If this shows anything other than "disabled" then you can try entering this:

netsh interface tcp set global autotuning=disabled

This should return "OK".

At this point we tried browsing the web - and lo-and-behold it was browsing at a more normal (ie fast) speed.

If you want to set it back to the way it was, you can try this:

netsh interface tcp set global autotuning=automatic

A quick fix, but one that is worth remembering.