Slow performance playing Flash videos

Avast Free Antivirus / Premium Security
1

I see some slow performance playing Flash videos in Google Chrome and Mozilla Firefox (tested both). I use Windows 8 updated. I have a good Internet connection, 20 MB.

I tried stopping Avast! and i saw that this is a problem with Avast!, not my PC.

Greets

2

Yes I noticed it playing back some video in Youtube.
I first thought the file hadn’t buffered, but once I disabled the shield, the file was
instantly available to play.