Linux moving incredibly slow

I do not have an extensive Linux background, but you could call me "intermediate" I guess.

I have Red Hat Enterprise 4 for a work application. I needed to (and did) build 10 systems with the following:
2x E5345 2.33 Xeon
Intel S5000XVN-SAS
8GB Kingston Value RAM
2x 500GB HDDs in RAID 1 via mdadm
GeForce 7950

So my problem is this: I have 3 of these systems hooked to a router right now. When I have eth1 enabled (the ethernet port which is connected), the computer runs insanely slow. I waited 5 minutes for a terminal to come up. When eth1 is disabled, the entire system runs perfectly.

The drives are partitioned with 16GB of swap space each, also in RAID1. During boot, "enabling swap space" fails, even though the fstab is set up properly. This happens with or without eth1 being enabled within the OS.

If anyone has heard of this problem, or knows the best community to go ask (IRC or somthing maybe, anything goes) I'd be very grateful.

Yes it might be the DNS.

Or If you enabled the kerberos authentication or LDAP or samba pam at authentication configuration this might be.

When the system going to start up this services try to connect to the kerberos/LDAP server and obviously can't reach them.

So you need to wait for 5 min. to start up the system.

Check the authentication configuration window at setup select just the MD5 password and shadow password. (terminal / setup / authentication configuration)

As well setup the /etc/resolv.conf for your whole network. (this file contains your subnet's all hosts and names to resolv them)

Servers, clients.

Laz.