Turbo mode is built into the CPU, you don't need a driver.
I can concur from experience with the other response. I have an HP dv8t-1000 and had the same apparent problem. I installed the Intel "widget" that goes on your desktop and visually shows you when the turbo boost is operating. It suddenly stopped ever showing the processor in boost mode, I checked and saw the driver had a yellow problem indicator and the words "not operating" and proceded to use HP online tech support, who sent me a newer driver to download and the same thing happened: the driver showed that it was not operating and the turbo "meter" on my desktop showed no action. Then it came to me: I had recently changed my power plan and dramatically reduced everything, including processor speed. I had, in effect, underclocked my cpu! When I changed the settings back for "plugged in" status, the turbo bar went crazy again, constantly jumping up when new software was started and used, etc. Oh, and, reinforcing what the other contributor said, I had ultimately left the computer with the "turbo boost technology driver" uninstalled! So the only question is: why does such a driver exist? Have you noticed there is no support for it, not even a driver download, on Intel's web site? Should be a clue, lol!
Turbo Boost Tech. Driver exists for HM55 , HM57 Intel Express chipset , those chipsets somewhy need the driver for the technology to operate , PM55 chipsets have the driver somehow built in the cpu and the technology works automatically =D
And hey , davidmarie , plz , what is this turbo bar are you talking about ? may I have a link or something ? xD