I had the opportunity to test out a few settings on a CS server to see what FPS numbers I could get with which settings. I did this on a fresh install of windows 2003 on a Conroe box, using an empty 32 man CS 1.6 instance created in Cortex as my test platform. Here's my super scientific findings:
With the stock config, CS was running at 74FPS.
Turning on the hires timer upped it to 171FPS.
Adding "-tickrate 100" to the command line did absolutely nothing. It still ran at 171FPS.
Changing sys_tickrate from 200 to 10000 increased it to 512FPS.

In all cases the empty server used 0% CPU and 62M RAM.
Here's where things got fun and where my test ultimately failed. The "ACPI Multiprocessor PC" driver was installed. I changed that to the "MPS Multiprocessor PC" driver to see what it would do to performance. After setting it and Windows rebooted it lost my NIC and a number of devices. Scratch that idea then. I tried installing the "ACPI PC" driver, hoping to remove SMP processing from the loop. After setting this and rebooting the server got stuck in a reboot loop, rebooting immediately after showing the windows2003 loading screen. Sheesh. If this were one of your systems in production it would mean OS reload time. So please, everyone, it'll be easier on all of us if you leave things running at 512FPS.