First try looking into your BIOS and see if Intel Turbo Boost Technology is enabled. If there are no options for that in the BIOS then Turbo Boost Tech is more than likely enabled. Boot to Windows and set the power plan from HP recommended to "High Performance". This forces the CPU to be at 100% frequency state (.ie. 2.0 - 2.9 GHz). If the frequency is still 2.0 GHz, you may have HP Thermal Assistant software installed and is set to "quiet" mode. Note that "quiet" mode disables Turbo boost technology so the CPU won't get as hot and the fan won't speed up. So set the mode to "maximum cooling." Turbo boost should now be working. Confirm by downloading prime95 and torture test with only 1 thread. If turbo boost doesn't work, reinstall HP thermal assistant software. Then Reset Defaul Power plan by following this link
http://www.sevenforums.com/tutorials/950-power-plan-restore-default-settings.html . This should make your Turbo boost technology 100% working. Here's a screenshot with max turbo boost working with prime95: