Yes, indeed. The problem isn't that I don't know the CPU speed, but that I can't get cpu-freq to work, and I can't get throttling to occur. All the error messages I get relate to the cpu driver (or a lack thereof).
I compiled the kernel myself and made sure to include all the ACPI stuff, plus the relevant power governots and the P-states driver. I also tried both with and without the Intel Enhanced Speedstep (which seems to be deprecated), to no avail.
Most of the guides I see tell people to modprobe the module - but I've compiled mine in, so I assume it should all just be there all the time. Should recompile with all these things as modules instead?