Excessive CPU Usage

Since upgrading from version 2.6 to 2.8.4 (and now 2.8.5) my web host has been complaining that my blog is using too much CPU. My blog is a small, non-commercial blog and I only get about 700 legitimate hits per day, i.e. legitimate as measured by Sitemeter.

Here’s the most recent message I got from my web host:

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10-25-2009
domain: theglitteringeye.com
CPU usage: 2.98
MEM usage: 0.02
MySQL usage: 0.1
Top Process %CPU 89.0 /usr/bin/php /home/xxxxxx/public_html/index.php
Top Process %CPU 76.0 /usr/bin/php /home/xxxxxx/public_html/index.php
Top Process %CPU 68.0 [php]

10-26-2009
domain: theglitteringeye.com
CPU usage: 2.03
MEM usage: 0.05
MySQL usage: 0.1
Top Process %CPU 70.0 /usr/bin/php /home/xxxxxx/public_html/index.php
Top Process %CPU 59.0 /usr/bin/php /home/xxxxxx/public_html/index.php
Top Process %CPU 49.0 /usr/bin/php /home/xxxxxx/public_html/index.php

The following tests have been performed: I visit your website and checked several posts, where the php processes that where running under your account where using a small amount of CPU usage (3-4%). However when changing the category, the CPU usage went to 30-45% on each change:

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
32537 xxxxxx 23 0 29392 19m 4424 S 33.6 0.3 0:00.71 php

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When I received that message I was only running two plug-ins: AKismet and WP-Super Cache. Since receiving it, despite my misgivings, I have deactivated both of them.

Anybody have any ideas on how I can trouble-shoot this problem?