For the last few days I've been experiencing slow browsing speeds only on particular websites. Some websites (such as flickr) are completely unaccessible, some are accessible but not all features work (such as gametrailers) while others (such as the penny-arcade forums) just run very slowly. This problem seems to be the worst during the afternoons.
I've checked with my ISP, and they aren't having any known connection problems at the moment. I've also changed my DNS settings, checked I'm not using a proxy, scanned for viruses, tried the same websites with IE, turned off automatic updates and checked I'm not running any P2P programs. None have worked. I've never used a download/upload limiter and am currently using Comodo Internet Security for my firewall.
[strike]My brother says he isn't getting any problems, but I haven't been able to get on his computer to check the same websites.[/strike]
EDIT: I got on to his computer, finally. He is having the same problems as I am.
Anybody got any clue as to what could be causing this?