It will enable older software that runs on fewer cores, to perform better on newer hardware. Turbo Boost is a CPU feature that will run CPU clock speed faster than its base clock, if certain conditions are present. The i5-2500K has a higher turbo clock boost.For some games, a cpu with a higher clock speed, or in a technical name IPC (Instructions per clock), has better results than other CPU's with higher core count and lower core speed.Larger programs are divided into threads (small sections) so that the processor can execute them simultaneously to get faster execution. This architecture greatly increases the performance of a system that is running concurrent applications.

Each core can handle a separate stream of data. The benefit of having more cores is that the system can handle more threads. Data/instructions which have to be processed can be loaded from the fast L2 and the CPU does not have to wait for the very slow DDR RAM The i5-2500K has higher Level 2 Cache.The Core2 Duo E8400 is more power efficient and generates less heat.

Core 2 duo 2.4 ghz vs i5