When I start to surf, the speed is okay, but I have notice that the speed gets slower as I surf and more slower download and upload and also web surfing get slower as I surf many hours, anyone has the same problem as me!

Yes I agree, when I start off in the morning it's okay, but come the the afternoon, it can be a crawl. I think though that this is just replicating the normal patten of internet use. When I used dial up, it used to be good in the morning but poor in the afternoon.