Modernbill Is Really Slow / Mysql Optimizations

Modernbill v5 is extremely slow. It takes about 2-3 seconds to get to the next page or refresh. It took 5 seconds after clicking 'reports' tab.

In order process, it takes 3-5 seconds just to show the add-ons or update them after hitting "save add-ons". This is unbelievable. I'm using Firefox.

I'm on a cable connection

Server specs:
Dual Xeon 3.4GHz HT
4GB Memory
MySql 5
PHP 5.2.5
Apache 2.2

I applied these optimizations as suggested by an MB tech

Quote:

At the ModernBill level, We have the following custom configurations in our /lib-modernbill/include/config/config.php file:

$CONF["dbType"] = "mysqli";
$CONF["forceCLICurl"] = 0;
$CONF["enableSharedMemoryLocaleCache"] = true;
$CONF["enableSharedMemoryAdminCache"] = true;
$CONF["adminCacheSeconds"] = 300;
$CONF["enableSharedMemoryMBPathCache"] = true;
$CONF["smarty"]["enableCaching"] = true;
$CONF["smarty"]["cacheLifetime"] = 0;
$CONF["smarty"]["enableCompileChecking"] = false;

At the PHP level, we have the following in our php.ini (some of these were recommended in our documentation to start with):

max_execution_time = 300
memory_limit = 128M
error_reporting = 2039
display_errors = Off
register_globals = Off

/etc/my.cnf

[mysqld]
local-infile=0
datadir=/var/lib/mysql
skip-locking
skip-innodb
skip-networking
safe-show-database
query_cache_limit=1M
query_cache_size=32M ## 32MB for every 1GB of RAM
query_cache_type=1
max_user_connections=500
max_connections=1500
interactive_timeout=10
wait_timeout=28800
connect_timeout=20
thread_cache_size=128
key_buffer=512M ## 128MB for every 1GB of RAM
join_buffer=4M
max_connect_errors=20
max_allowed_packet=16M
table_cache=1024
record_buffer=4M
sort_buffer_size=4M ## 1MB for every 1GB of RAM
read_buffer_size=4M ## 1MB for every 1GB of RAM
read_rnd_buffer_size=4M ## 1MB for every 1GB of RAM
thread_concurrency=8 ## Number of CPUs x 2
myisam_sort_buffer_size=64M
server-id=1
collation-server=latin1_general_ci

[mysql.server]
user=mysql

[safe_mysqld]
err-log=/var/log/mysqld.log
pid-file=/var/lib/mysql/mysql.pid
open_files_limit=8192

[mysqldump]
quick
max_allowed_packet=16M

[mysql]
no-auto-rehash
#safe-updates

[isamchk]
key_buffer=64M
sort_buffer=64M
read_buffer=16M
write_buffer=16M

[myisamchk]
key_buffer=64M
sort_buffer=64M
read_buffer=16M
write_buffer=16M

[mysqlhotcopy]
interactive-timeout