You have some power setting wrong that's why it goes to 3.4ghz.
Intel Turbo Boost is a technology implemented by Intel in certain versions of their Nehalem- and Sandy Bridge-based CPUs, including Core i5 and Core i7 that enables the processor to run above its base operating frequency via dynamic control of the CPU's "clock rate". It is activated when the operating system requests the highest performance state of the processor. Processor performance states are defined by the Advanced Configuration and Power Interface (ACPI) specification, an open standard supported by all major operating systems; no additional software or drivers are required to support the technology. The design concept behind Turbo Boost is commonly referred to as "dynamic overclocking". -Wikipedia
I don't believe turbo has anything to do with a power setting