Citing (printing, saving, sending) official Intel documentation won't do?
A letter is what the CC agent told to get, and I was honestly surprised at the request. The L5639 is actually a 6-core version of the L5630 and it's actually not on ARK, but I have found an Intel document online that shows the specifications of the L5639.
Isn't the CPU simply in power-saving mode?
Get a Prime95 instance going and check CPU-Z. See what clock comes up.
One of their support staff eventually confirmed to me that they lower the speed because it was tripping electrical circuits. I've checked a few utilities like CPU-Z, wmic from the cmd line, and HWINFO which told me Turbo was off as well.