I ran into this issue couple of weeks ago,and the issue is I believe caused by installing SP1 for Windows 7 x64.Avast slows down my internet traffic (Youtube and other video streaming services especially).Are you aware of this issue? Are you working on getting it fixed? When I turn of the web shield,everything speeds up and youtube loads up much faster.
I have the same problem with Youtube and Dailymotion, but I have Windows XP home edition SP3. I always had the problem with AVAST. But I just installed again the complete AVAST 6.0.1091 free edition and add the .dll files that
pelochon wrote in the thread about the problem with WMP11 becoming red because of the script shield and youtube seems to be a little more slower. Until now I had this AVAST version but I uninstalled the script shield and Youtube worked as well as with the previous versions (so not perfectly but well), and with the script shield it seems to be a little slower.
Just after the problem with WMP11 red, I uninstalled AVAST and installed the trial version of the newest KASPERSKY version ... even if this antivirus is very heavy, youtube worked perfectly. I noticed when I checked my connection speed, with speedtest.fr, on firefox 3.6.16, I had approximately 9.5 Mbps. With AVAST (5 & 6), I find maximum 5.2 - 6 Mbps.
AVAST seems to have an impact on firefox, so on youtube ...
Now I am used to have this problem, I have to close firefox and open it again and I can watch 2-3 videos without problems.
With AVAST 6, it seems to be slower