The new Core i5-2500K simply crushes its main rival, the Phenom II X4 975 (3.6 GHz), in almost all applications. In some games with an entry-level add-on video card installed, however, the Phenom II X4 975 was faster than the Core i5-2500K (it is important to remember that with high-end video cards the CPU usually doesn’t play a significant role in performance). The Core i5-2500K is also way faster than the Core i5-661, partly because of the new microarchitecture, partly because it is a true quad-core CPU (the Core i5-661 is a dual-core CPU with Hyper-Threading technology). The truth is that AMD is very delayed with the launch of the Phenom II X4 975, a CPU that should be released months ago.

Intel was saying that the integrated video of “Sandy Bridge” CPUs would be twice as fast as the integrated video of “Clarkdale” CPUs. Giving the right circumstances, they were right. In fact, this is the first time that you can play DirectX 9 games with an integrated video solution at a decent frame rate, if you minimize all graphics settings. With the DirectX 10 game we ran (Far Cry 2), the integrated video of the Core i5-2500K achieved very low frame rate, even with all image quality settings at their lowest values, meaning that you won’t be able to play this game without installing a “real” video card.

There is still one important question to be considered. Who buys a USD 200 CPU to run integrated video? Usually people that need processing power but won’t be playing games anyway.

We were satisfied with the overclocking capability of the Phenom II X4 975: we could easily put it to run at 4.26 GHz, an 18.3% increase above the CPU’s standard clock, which is a very good mark for an AMD CPU.

Now, the new Core i5-2500K creates a new chapter in overclocking history. We could put it to run at 4.84 GHz, a 46.7% increase in the CPU internal clock rate, which is unheard of – and keep in mind that we are not into overclocking! Reviewers from other websites could put this CPU to run at 5.1 GHz! It is very important to keep in mind that we got an engineering sample, and the final product may not have such a fantastic overclocking potential. Only time will tell.

In summary, the new Core i5-2500 is the best CPU today in the USD 200 range, bringing an impressive performance gain over the competition and the previous-generation Core i5. If you like overclocking, you should spend USD 11 more and buy the “K” version, which has the best overclocking potential of any CPU we’ve ever reviewed.