You can also , and i recommend, downloading the voodoo control from the market. It will tell you if it is enabled and give you quite a bit more useful settings for the kernel. In addition, for the voltage, you should get voltage control from the market as well. It allows you to set custom voltage settings for kernels that support it. There is a whole thread on voltage settings so check that out. Remember that some settings work for most, some for no one. It is very device dependent, I have been playing around with the voltage settings for about a week and havent come up with something that is stable enough to use outside of "stock", I think mine is weird though and just needs to be re-flashed