I would suggest running the Intel® Processor Identification Utility to determine if the processor is being properly recognized.
You can download the Intel® Processor Identification Utility at:
http://www.intel.com/support/processors/tools/piu/
Intel processors do not required any driver since they are software independent, however the in some cases the operating system requires a driver that is provided by the operating system developer, for it to properly recognize the processor.
So if the Intel® Processor Identification Utility reports the processor as the correct one, and detects both cores, then a clean installation of the operating system would be a good idea, make sure that the BIOS is detecting the right processor, and install the latest BIOS version available.