nehalam is the codename for an Intel processor microarchitecture, successor for the core microarchitecture

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Nehalem is the codename for an Intel processor microarchitecture, successor to the Core microarchitecture. Nehalem processors use the 45 nm process. The first processor released was the desktop Cire i7. Which was released in November 2008.

RAM speed varies based on both the CPU's internal design, microarchitecture, front side bus speed, and chipset.

This depends on what type of A-Series you are talking about, but the i3 is better than the Pentium Dual Core although they are based on the same microarchitecture.