Strange networking problem

[starcastic]

Hi. I'm having a very strange networking problem. At first, my computer wasn't detecting my school's network at all. However, I updated the dhcp, and now it connects. However, it is REALLY slow. Like, to the point of not doing anything. It will get fast sporadically, for a few seconds, then slow to a crawl. Additionally, I hooked it up to my other computer, and manually assigned it an IP. When I tried to ping the other computer, a few packets would go at normal speed, and the rest would take a really long time, or not arrive at all. Any ideas?

My specs:

FC3 (it's not updated, because up2date doesn't work; it's too slow. it times out)

Chaintech ct-skt600 motherboard --> also, a weird note, which is perhaps relevant: in the motherboard specs, it says this for the LAN: "Supports 10/100 mb fast ethernet with external via vt6103 phy." external? the ethernet is built in. additionally, the network configuration utility sees it as a via vt6102 rhine II. Is this significant?

athlon 2700 xp

250 gb sata hd

512 mb ram

generic geforce4mx

[adrenaline]

look for things running in the background-
there is a gui monitor watches cpu usage. I usually assign it to the tool bar so I can watch to see if wierd things are happening. Sometimes conflicting apps will send cpu through the roof. In my case Alsa and oss were conflicting and my cpu would go to 100 % since oss isn't really used anymore I turned if off and I haven't had a problem since.
Also check as root in a term
/var/log/messages

[kkubasik]

there are 2 main causes for this

1) you have compiled ipv6 support into your kernel and activated it, but are using a router or network that does not support ipv6, resulting in incredably slow connection speeds
2)your dns servers are not resolving quickly or effectivly.

The best way to test this is to try downloading a file, should it run quickly once it gets started, then it means that your DNS servers are the culprit, and you must point to new ones, or contact your ISP about them. However, should the download run incredably slowly also, most likely its the ipv6. If this seems the case, pleae post the output of

ifconfig eth0