Web Washer is a web page filter which reduces commercials from the pages you are browsing, so, it is natural that it should slow down your browser when you disable it.
BTW, Lars-Eric, igor is one of Avast! team. So, it would be suitable for you to pay attentions to what he says rather than I, though.
What browser are you using, I was able to scroll down the Thread List of Pro/Home forum whilst the page was still loading. I'm on a dial-up connection (so my page may well take longer to load) and using firefox in conjunction with Web Shield.
The same is true with Maxthon, but there is a slight pause before I can scroll, but well before the page completes loading.
There is no pause setting as far as I'm aware in Web Shield.
Err...DavidR, you can choose pause Web Shield from pause provider option through right clicking Avast task tray icon. This doesn't stop the proxy function of WS but prevent it scanning the contents. Also, I think it is not the matter of the speed of the connection but that of the PC...