Intel Core i7-3610QM processor seems to have only 3 cores, 6 threads (instead of 4 cores, 8 threads)

A year ago, I bought an ASUS G75VW-T1066V laptop with an Intel Core i7-3610QM processor.

The Intel specifications (http://ark.intel.com/products/64899/Intel-Core-i7-3610QM-Processor-6M-Cache-up-to-3_30-GHz ) say that this processor contains 4 Cores and supports 8 Threads.

The Intel Processor Identification Utility also claims "Active cores per processor: 4, Disabled cores per processor: 0".

But Windows7-64 in its "performance" section sees only 6 threads.

So does CPU-Z: "3 cores, 6 threads".

So does Speccy from Piriform: "3 cores, 6 threads".

My questions: do I have a faulty i7-3610QM processor?

Or do I have to activate something so that the fourth core and the eights thread become operational?