Intel Turbo Boost is a technology implemented by Intel in certain versions of its processors that enables the processor to run above its base operating frequency via dynamic control of the processor's clock rate. Processor generations supporting this feature are based on the Nehalem (Turbo Boost 1.0), Sandy Bridge (Turbo Boost 2.0), Ivy Bridge, Haswell, Broadwell, Skylake and Broadwell-E (Intel Turbo Boost Max 3.0) microarchitectures, while the examples of Turbo-Boost-enabled processors are the Core i5 and Core i7 series.
Turbo Boost 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".
source:
https://en.wikipedia.org/wiki/Intel_Turbo_Boost
As far as your Intel® Core 2 Quad Processor Q9500 goes, it doesn't have the Turbo Boost feature,
specs:
https://ark.intel.com/products/37159/Intel-Core2-Quad-Processor-Q9500-6M-Cache-2_83-GHz-1333-MHz-FSB
(Scroll down a bit and look under "Advanced Technologies" section.)
For example, my Skylake build's CPU, i5-6600K, has Turbo Boost feature,
specs:
https://ark.intel.com/products/88191/Intel-Core-i5-6600K-Processor-6M-Cache-up-to-3_90-GHz
My CPU base clock is 3.5 Ghz while with Turbo Boost it rises up to 3.9 Ghz. Since i have K-series CPU that has unlocked multiplier, i can overclock my CPU even further and run it with much higher clock than Turbo Boost can do, e.g 4.2 Ghz. Note: when CPU is manually overclocked, the Turbo Boost feature will be disabled.