Slow Loading Website Even After Following Tutorials

i am trying to optimize my dedicated server to host one website (php-nuke platnuam 7.6v2b5 taking 1min to 1min 30secs to load). ive read the tutorials and it does not seem to make a difference no matter what i try. if one of you guys could kindly point out what could possibly be the problem i would be very greatful.

Kernel Version:
2.6.18-8.1.14.el5
Hardware:
Motherboard SuperMicro X7DBR-E Intel Xeon DualCore DualProc SATA 2Proc

Processor Intel Xeon-Clovertown 5335-QuadCore-LV 2GHz

RAM slot 1 Generic 1GB 667ECC FB-DIMM DDR2 1GB
RAM slot 2 Generic 1GB 667ECC FB-DIMM DDR2 1GB
RAM slot 3 Generic 1GB 667ECC FB-DIMM DDR2 1GB
RAM slot 4 Generic 1GB 667ECC FB-DIMM DDR2 1GB
RAM slot 5 Empty
RAM slot 6 Empty
RAM slot 7 Empty
RAM slot 8 Empty

Drive Controller Mainboard Onboard SATAII Controller

Hard Drive 1 Western Digital WD Caviar RE 16 WD2500YS 250GB
Hard Drive 2 Western Digital WD Caviar RE 16 WD2500YS 250GB

Cpanel:
WHM 11.11.0 cPanel 11.15.0-R17665

Top output:
top - 16:44:51 up 17:42, 1 user, load average: 0.01, 0.00, 0.00
Tasks: 154 total, 1 running, 153 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 0.3%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 3369376k total, 2478128k used, 891248k free, 228052k buffers
Swap: 2096440k total, 0k used, 2096440k free, 1964784k cached

Vmstat:
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 0 0 891124 228272 1964832 0 0 34 21 99 81 1 0 98 0 0
0 0 0 891124 228284 1964824 0 0 0 9 1045 161 0 0 100 0 0
1 0 0 891124 228292 1964832 0 0 0 3 1031 130 0 0 100 0 0
0 0 0 891124 228300 1964832 0 0 0 3 1045 157 0 0 100 0 0
0 0 0 891000 228308 1964832 0 0 0 7 1035 144 0 0 100 0 0

Distro:
REDHAT Enterprise 5 i686

Mysql:
4.1.22-standard

Apache:
Server version: Apache/2.0.61
Server built: Oct 17 2007 14:55:40
Cpanel::Easy::Apache v3.2.0 rev2623

php:
PHP 5.2.4 (cli) (built: Oct 17 2007 15:00:59)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies

things from the tutorials section ive tried:
this website/showthread.php?t=549666
this website/showthread.php?t=579135
this website/showthread.php?t=340239 (only did 4. Tuning sysctl.conf from here)