The difference between the Intel® Core™ i5-2500 and then Intel Core i7-2600 come down to 2 things. Intel Core i7-2600:
-Hyper-Threading (support for 8 threads)
Intel Core i5-2500:
The non-K processors have TXT (Trusted Execution Technology) and VT-d (directed I/O for virtualization). Now if you change to pick up an Intel Core “K” processor like the Intel Core i7-2600K and the Intel Core i5-2500K they are just like the non-k model except for the above listed features and the K processors have Intel HD 3000 graphics and have an unlocked multiplier making it very easy to overclock these processors to well above 4GHz.
Intel Enthusiast Team