Não entendo o que está acontecendo. De uma hora pra outra ficou uma lentidão terrível.
Segue meu proftp.conf

# This is a basic ProFTPD configuration file (rename it to
# 'proftpd.conf' for actual use. It establishes a single server
# and a single anonymous login. It assumes that you have a user/group
# "nobody" and "ftp" for normal operation and anon.

ServerName "ProFTPD Server mycompany"
ServerType standalone
DefaultServer on

# Allow FTP resuming.
# Remember to set to off if you have an incoming ftp for upload.
AllowStoreRestart on

# Port 21 is the standard FTP port.
Port 21
# Umask 022 is a good standard umask to prevent new dirs and files
# from being group and world writable.
Umask 022

# To prevent DoS attacks, set the maximum number of child processes
# to 30. If you need to allow more than 30 concurrent connections
# at once, simply increase this value. Note that this ONLY works
# in standalone mode, in inetd mode you should use an inetd server
# that allows you to limit maximum number of processes per service
# (such as xinetd)
MaxInstances 10

# Set the user and group that the server normally runs at.
User nobody
Group nogroup

# Normally, we want files to be overwriteable.
<Directory /*>
AllowOverwrite on

# Needed for NIS.
PersistentPasswd off

# Default root can be used to put users in a chroot environment.
# As an example if you have a user foo and you want to put foo in /home/foo
# chroot environment you would do this:
DefaultRoot /home/myuser myuser

Desde já agradeço qq. ajuda.