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There is a lot more to that output. This tells us what is installed but not the settings. Is the accelerator loaded and activated? Is zlib.compression On (doubt it since it will cause other problems)? Many options. I have good success with mmcache as an accelerator/precompiler/cache
It appears that the Linux kernel was recently recompiled and the server rebooted. The Apache config is important to know and optimize.
Where is the MySQL server? Are you using persistent connections? How many connections are being held open (maybe turn persistent off in mainfile.php and see how it runs)?
Do you want to show us the site?