I've installed CentOSv5.2, and everything *seems* to be working fine.

The exception is that there is a HUGE amount of latency in the HTTP connection. Some sites load, though slow, and some sites don't load at all (though the page titles come up in the Title Bar). What could the problem be?

For example, CNN.

Could it be the cable? I'm using cat-5. It's about 15 feet from the router. Too long? Bad cable?

Something else? I've disabled SElinux, but could it be some other firewall issue?

I keep coming back to bad cable. Am I wrong to think it's not a software issue?

My next step is to haul it closer to the router and use a different cable.

But just for speculation, does anything in my description jump out?

Cat 5 cable can easily take distances upto 100 meters without much of latency. But if the cable itself is defective then you might just try to change it. But the distance does not seem to be the cause. Have you tried connecting some other machine or trying on other distribution? Trying out on some Live Distro could give you some idea if the problem is hardware.

Are you using Firefox? I have read the same issues for Fedora 9 and 10. Check this:

Disable IPv6 in Firefox

If this doesn't solve your problem, is CentOSv5.2 using NetworkManager or the network deamon? Fedora 9 and 10 also had problems like that. Check this:

Fedora NetworkManager problem