Supported tickrates on x86* archs are 100, 500 and 1000. Other values may work, but may not. Historically, x86 was at 100, but was moved to 1000 during the 2.5 development line. This increases overhead slightly, but helps timeslice accounting resolution and a host of other things. the way to change the tick rate is to change the HZ constant that is defined in include/<your-architechture>/param.h
#define HZ whatever
Then, recompile your kernel.
I would not recommend doing this, but would be curious to hear how it goes if you try to do it. There are a number of better optimaztions you could make in the kernel, I believe.
Your HZ rate is almost invariably 1000 if you are on an x86* architecture. If not, you can find out by looking at the source for your built kernel at include/<your-architechture>/param.h
best of luck