Our lab managed to get hold of two very interesting dual-core solutions from AMD manufactured with 45nm process. These processors will be positioned as primary competitors to Intel Core 2 Duo and looks like they have very good chance to succeed. As we have already reported in our news, AMD will be releasing new dual-core CPUs based on the cores made with the latest 45nm process. In other words, the Deneb core that has received a lot of great feedback will arrive in a new incarnation giving birth to new highly promising processor families known as Callisto and Regor. Due to more than affordable price of only around $100, these CPUs will finally become the long awaited worthy rivals to Intel Core 2 Duo. The major difference between Phenom II X2 and Athlon II X2 is evidently in the configuration of their cache-memory system. Phenom II X2 has a 6MB L3 cache typical of most Phenom II processors. Athlon II X2 has no L3 cache, but instead – what a surprise! - boasts twice as large L2 cache. The modular structure of the Deneb core has definitely worked very well for AMD here. It allowed AMD engineers to combine the L2 cache memory of the two working processor cores with the L2 cache memory of the disabled cores. While dual-core CPUs on 65nm cores could only compete against Intel Pentium solutions, the new Athlon II X2 and Phenom II X2 attempt much more than that. Athlon II X2 250 overclocked to 3.9GHz with the Vcore increased by 0.175V above the nominal and remained absolutely stable throughout the tests. The results of our Phenom II X2 550 overclocking experiments confirm this assumption as well. This processor remained stable at 3.98GHz frequency with the core voltage increased by 0.15V.