I was having problems getting the cpuspeed daemon running after I switched to the ElRepo mainline kernel on CentOS 6.5. It turns out the newer kernel defaults to using the intelpstate driver instead of acpipstate and this can cause issues with the stock cpuspeed config. If you are using the intel_pstate driver and having issues add this to the kernel boot parameters:
This will force the kernel to use the acpi driver and allow cpuspeed to work properly.
Full credit to Joshua Kramer