Slow network while running Archlinux

Question

Hi there,
Recently (and, that's the weirdest part, recently only) the network have been really slow. From what I see when I'm running Windows, I assume I actually only get a fraction of the speed I should get when I'm running ArchLinux.
For instance, when I'm alone at home, I have an acceptable connection with ArchLinux (though I still can't play online games : too much lag. I have to boot on Windows for that).
And when some roommates are here, I have an utterly slow connection which makes it barely possible to load a page from ArchLinux's wiki (though I can do it with Windows with no problem, and can still play online games with a bit of lag).
It's been lasting for the past three months, so I'm pretty sure it's no coincidence : there's something wrong.
I've been reading some pieces of the wiki and tried to find what's wrong with my configuration. I did find that the hostname from the rc.conf and hosts files were different, but changing that didn't solve the network problem.
Here is my configuration :
/etc/rc.conf
# /etc/rc.conf - Main Configuration for Arch Linux
# LOCALIZATION
# LOCALE: available languages can be listed with the 'locale -a' command
# DAEMON_LOCALE: If set to 'yes', use $LOCALE as the locale during daemon
# startup and during the boot process. If set to 'no', the C locale is used.
# HARDWARECLOCK: set to "", "UTC" or "localtime", any other value will result
# in the hardware clock being left untouched (useful for virtualization)
# Note: Using "localtime" is discouraged, using "" makes hwclock fall back
# to the value in /var/lib/hwclock/adjfile
# TIMEZONE: timezones are found in /usr/share/zoneinfo
# Note: if unset, the value in /etc/localtime is used unchanged
# KEYMAP: keymaps are found in /usr/share/kbd/keymaps
# CONSOLEFONT: found in /usr/share/kbd/consolefonts (only needed for non-US)
# CONSOLEMAP: found in /usr/share/kbd/consoletrans
# USECOLOR: use ANSI color sequences in startup messages
LOCALE="en_US.UTF-8"
DAEMON_LOCALE="no"
HARDWARECLOCK=""
TIMEZONE="Europe/Madrid"
KEYMAP="es"
CONSOLEFONT="iso01-12x22"
CONSOLEMAP=
USECOLOR="yes"
# HARDWARE
# MODULES: Modules to load at boot-up. Blacklisting is no longer supported.
# Replace every !module by an entry as on the following line in a file in
# /etc/modprobe.d:
# blacklist module
# See "man modprobe.conf" for details.
MODULES=()
# Udev settle timeout (default to 30)
UDEV_TIMEOUT=30
# Scan for FakeRAID (dmraid) Volumes at startup
USEDMRAID="no"
# Scan for BTRFS volumes at startup
USEBTRFS="no"
# Scan for LVM volume groups at startup, required if you use LVM
USELVM="no"
# NETWORKING
# HOSTNAME: Hostname of machine. Should also be put in /etc/hosts
HOSTNAME="localhost"
# Use 'ip addr' or 'ls /sys/class/net/' to see all available interfaces.
# Wired network setup
# - interface: name of device (required)
# - address: IP address (leave blank for DHCP)
# - netmask: subnet mask (ignored for DHCP) (optional, defaults to 255.255.255.0)
# - broadcast: broadcast address (ignored for DHCP) (optional)
# - gateway: default route (ignored for DHCP)
# Static IP example
# interface=eth0
# address=192.168.0.2
# netmask=255.255.255.0
# broadcast=192.168.0.255
# gateway=192.168.0.1
# DHCP example
# interface=eth0
# address=
# netmask=
# gateway=
interface=
address=
netmask=
broadcast=
gateway=
# Setting this to "yes" will skip network shutdown.
# This is required if your root device is on NFS.
NETWORK_PERSIST="no"
# Enable these netcfg profiles at boot-up. These are useful if you happen to
# need more advanced network features than the simple network service
# supports, such as multiple network configurations (ie, laptop users)
# - set to 'menu' to present a menu during boot-up (dialog package required)
# - prefix an entry with a ! to disable it
# Network profiles are found in /etc/network.d
# This requires the netcfg package
#NETWORKS=(main)
# DAEMONS
# Daemons to start at boot-up (in this order)
# - prefix a daemon with a ! to disable it
# - prefix a daemon with a @ to start it up in the background
# If something other takes care of your hardware clock (ntpd, dual-boot...)
# you should disable 'hwclock' here.
DAEMONS=(hwclock @syslog-ng dbus !network networkmanager dhcpd ifplugd netfs @crond @sshd)
/etc/resolv.conf
# Generated by NetworkManager
nameserver 62.42.230.24
nameserver 62.42.63.52
/etc/hosts
# /etc/hosts: static lookup table for host names
#<ip-address> <hostname.domain.org> <hostname>
127.0.0.1 localhost.localdomain localhost
::1 localhost.localdomain localhost
# End of file
I tried commenting either of the DNS servers, without any changes.
I also tried with two different network daemons, NetworkManager and Wicd.
Is there something wrong with my configuration ? Is there something I can do to find out where does this problem may come from ?

Answer 1

Re-read this section on rc.conf and also cross-refer with the various items such as netcfg, as well as taking note of the single network approach and what you should do in #2 re: network daemon vs. your config with networkmanager:
https://wiki.archlinux.org/index.php/Rc.conf#Networking
Take a look at pdnsd as an alternative way to configure DNS lookups, also check out OpenDNS and Google's DNS as potential alternative nameservers so that you don't rely on your ISP's services.
https://wiki.archlinux.org/index.php/Pdnsd
http://www.opendns.com/
http://code.google.com/speed/public-dns/
Let us know if that makes it better.
NB: The DNS bit is an alternative approach that does not necessarily solve your issues though might be a desirable configuration.