Here is a little trick that will assist in squeezing the maximum RAM out of your Kloxo vps.
This will modify how your MySQL functions. The main draw back to this, is the fact that it will break roundcube webmail functions, due to innodb getting dropped. (more info at: http://forum.lxcenter.org/index.php?t=msg&th=15693&start=0&)

Edit your my.cnf file

1.>Login to SSH
2.>type nano /etc/my.cnf (you may prefer vi over nano – if you want nano, use yum install nano)
3.> Paste under the section labeled [mysqld]

#####RAM TWEAK#####
skip-external-locking
skip-slave-start
skip-bdb
skip-innodb
skip-name-resolve

# Global mem settings
key_buffer = 24M

max_connections = 200

# Per client mem settings

sort_buffer_size = 4M
read_buffer_size = 4M
binlog_cache_size = 2M

max_allowed_packet = 12M
thread_stack = 128K

table_cache = 128
thread_cache = 256
thread_concurrency = 4

myisam_sort_buffer_size = 1M
tmp_table_size = 12M
max_heap_table_size = 12M

wait_timeout = 200
interactive_timeout = 300
max_connect_errors = 10000

query_cache_type = 1
query_cache_limit = 1M
query_cache_size = 16M

[mysqldump]
quick
quote-names
max_allowed_packet = 16M

[mysql]
#no-auto-rehash # faster start of mysql but no tab completition

 

[isamchk]
key_buffer = 16M
#####END RAM TWEAK#####

Additional things you can do to reduce RAM useage is to switch from Apache, to Lighttpd.
You can also switch from BIND to DJBDNS if you do not have a constant change in domains on the system.