Yeah, they do. I think I downloaded something earlier, but I did a speed check and I'm still getting a full 20mb connection. My ping is horrendous, though. 500+ms. It's as if my connection is uploading and downloading and it's being bottle-necked. Fucking jokers, they are.
Mac im on Virgin 20meg.
Sopcast 133272 Russian one of wiziwig.
Had exactly the same problem as you, speed and tested and my ping was through the roof. Knocked sopcast off and it went back to normal.
Try the address above, it's Russian and takes ages to get going. Just leave it and eventually it'll buffer and grace you with a crystal clear picture.