crazy cpu spikes all day long

Ok, I've been getting crazy CPU load spikes on/off very often, all day long. From what I see, it looks like exim/spam assassin plus mysql "skip locking". I have posted some info below. Any help is truly appreciated.

ps aux (when cpu load hit 22+) (note: cpu load spikes high rapidly, and decreases rapidly by itself, occassionally knocking apache down).

(attached file for ps aux results)

My info:
:fail (Default catch-all/default address behavior for new accounts in tweak settings)
MySQL 4.1
Exim 4.50
WHM / Cpanel 10.1 C23
Spam Configuration (Maximum Children = 2, everything else blank)
Mailscan (on)
Exim Dictionary Attack ACL
Dual Xeon / 2GB memory

 

Happened again, this time shot over 22 and taking a long time to go down, even after restarting Exim, cpanel.

File attached for ps aux results.

Looks like Horde is one issue

Code:

cpanel    9935 91.5  0.9 27408 19096 ?       R    18:48  22:51 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
root     22552  4.3  3.2 70248 66884 ?       S    18:56   0:44 spamd child
root     22553  2.2  1.2 28040 26112 ?       S    18:56   0:22 spamd child
cpanel   32617 84.5  0.9 27408 19092 ?       R    19:01  10:03 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    3399 61.2  0.9 28520 19884 ?       R    19:09   2:36 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    6683  0.0  0.3  9440 8136 ?        S    19:10   0:00 webmaild - serving 206.48.0.60
cpanel    6730 49.4  0.9 28568 20092 ?       R    19:10   1:41 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    7288  0.0  0.3  9440 8136 ?        S    19:10   0:00 webmaild - serving 206.48.0.60
cpanel    7290 45.8  0.9 28164 19668 ?       R    19:10   1:31 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    7299  0.0  0.3  9440 8136 ?        S    19:10   0:00 webmaild - serving 206.48.0.60
cpanel    7304 47.4  0.9 28568 19820 ?       R    19:10   1:34 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    7642  0.0  0.3  9440 8136 ?        S    19:10   0:00 webmaild - serving 206.48.0.60
cpanel    7643 43.7  0.9 28580 20072 ?       R    19:10   1:24 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
cpanel    8183 42.1  0.9 28620 19876 ?       R    19:12   0:16 /usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/base/horde/imp/message.php
mailnull  8467  2.0  0.1  8036 3592 ?        S    19:13   0:00 /usr/sbin/exim -bd -q60m

I ran /scripts/fullhordereset too

Ran TOP

Code:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 8183 cpanel    25   0 28488  19m 2732 R 48.9  1.0   3:46.40 php
32617 cpanel    25   0 27408  18m 2724 R 45.9  0.9  13:31.43 php
18483 nobody    25   0 28120  20m 4552 S 45.6  1.0   0:01.65 httpd
 7290 cpanel    25   0 28060  19m 2724 R 44.3  0.9   5:05.80 php
 7643 cpanel    25   0 28448  19m 2724 R 40.4  1.0   4:43.32 php
 3399 cpanel    25   0 28376  19m 2724 R 36.7  1.0   6:03.15 php
 9935 cpanel    25   0 27408  18m 2728 R 36.1  0.9  26:20.72 php
 7304 cpanel    25   0 28068  19m 2724 R 34.8  0.9   4:59.00 php
 6730 cpanel    25   0 28424  19m 2724 R 32.8  1.0   5:12.69 php

Running PHP 4.3.11 too