Networking :: Iptables Causes Browsing Slowdown?

I have noticed that when iptables is active on my router i get a noticeable slowdown on browsing. This is untraceable through traceroute:

Code:
traceroute -n www.a-site-here.com

finishes immediately and at the same time when loading the site on firefox I am getting timeouts.

I use firewall builder to configure iptables. I have removed all rules while trying to find the one causing the problem, but even disabling all rules does not solve the problem. So, by leaving only an "accept-all" rule on firewall builder(so i don't lock myself outside) I still get slowdowns. In this case

Code:
iptables --list-rules
gives:
Code:
-P INPUT DROP
-P FORWARD DROP
-P OUTPUT DROP

[Code]....