Intel Core 2 Duo is a dual-core processor with an initial letter of E, P, or T. Core 2 also offers a quad-core version of Core 2 Quad, denoted by the letters Q or the latest version of XQ. Intel Core 2 processors can process up to 4 instructions per cycle. As a result, Core 2 can be up to 33% more efficient at the same frequency. Core 2 are equipped with these technologies EM64T, XD bit, AMT2, SpeedStep.